Unluckily Daniele and I lost our way twice and the meeting in Fiesch failed; the second time we lost our way was in Grindelwald because the signs to Grosse Scheidegg are the same both for pedestrian and cars ... The times you read in the description don't take into account the time lost due to these mistakes (about 45 min.) and specifically I don't mention the mistake in Grindelwald that added 220 mt of extra-devilement (average slope of this climb we erroneously faced: 10%).
As told before, you leave main route in Mulenen following directions on the right to Aeschi and Krattingen. The climb is short and easy: you ride in shadow and reach Aeschi full of nice wooden little houses. Here you follow directions to Krattingen, and another descent begins taking you to the Thunersee, the lake you see on distance some kn you left Aeschi: above it the Niederhorn a well-known panoramic point of view to look at the Bernese Oberland group.
Once you are at the lake level, you ride parallel to the motorway and then on a specific and very safe lane of it: in this case you MUST follow directions with bicycles on it and be patient with the noise of traffic you hear till the beginning of Interlaken. (till here 40 km. 75 min. 160 mt. of devilement)
Once you pass the square blue sign saying "Interlaken" you'll meet another (bigger) one with directions to Wilderswil: so turn right according to this sign and you'll meet after a few kms the main route to Grindelwald (a drinking fountain on your left). The first stretch is not so great and you have to share it with lot of cars (today it's saturday: maybe during the week the amount of traffic is not so high). Turn left to Grindelwald (beware of cars on your way) and from now on you must always go straight on following the main route.
Some of the famous 4000 mt. peaks of these regions begins showing up (Monch , Eiger) but the best views are far to come; besides the slope begins to increase and some effort is required to exit from a set of harpins. Some stretch up and down (more up than down) and you reach Grindelwald (till here 60 km 135 min. 700 mt. of devilement) Take a picture of Eiger (you see also a piece of Jungfrau) and go on into the centre of Grindelwald leaving on your right the route to Kleine Scheidegg.
Always up and down you reach the Parking car at the beginning of the first true climb of the day which will turn to be quite demanding. The climb is a continous set of harpins with slope always around 9 - 10% and except for postal bus it's closed to motor vehicles: as the way is not wide at all you must remember that when you meet a bus in your way or in the opposite one you have to stop for a while and stay on the surrounding grass in order they can easily overtake you. Besides due to their peculiar and powerful horn you can easily be aware of the distance of a bus from you.
During the climb Grindelwald disappears immediately and you gain altitude between meadows and some tree: some little hills hide the view locally that is you can't see neither the way you just climbed neither the way you' re going to reach so at every bend some new stretch of the way turns up in front of you. Globally you see, at your right on distance the Eiger and some gletscher towards the very high Wetterhorn.
Some drinking fountains appear during the last kms and for the first time you see on distance what should be the end of the climb No doubts will be when you see also the first modern building along the way: it's the Grosse Scheiegg Hotel at the top of the climb. (till here: 70 km. 215 minutes 1600mt. of devilement)
Today, it's Saturday, it's plenty of bicycles (more than 100 I say). Eiger and Monch towards west, Wetterhorn southward, the trail for First Northward (First is the starting point of Faulhorn trekking that offers you some of the most famous views over the 4000's of Berner Oberland) and nothing meaningful towards east. After a break in order to feed myself, maybe due to the confusion, I start the descent leaving half of my food on a bench at Grosse Scheidegg ... (I'll be aware of that after 20km of descent ...).
Beware of two gratings you meet during the descent very dangerous: the first one appears immediately once you start the descent and the second one is near a fountain (the unique fountain I saw during the descent so stop here if you need water). Don't miss during the descent the view towards Wetterhorn (behind you during a flat stretch) and Rosenlaui Gletscher. The pavement is not so good and after Schwarzwaldalp you meet again cars. At the first cross I follow directions to Innertkirchen instead of Meiringen and went on following the places where are bus stop to be sure to avoid some tight stretch maybe not paved and only suitable for MTB ... I started the ascent to Grimselpass (till here 270 min. 96 km. 1600 mt. of devilement) finding out that I left half of my food on a bench at Grosse Scheidegg: worse start couldn't take place. Besides, it's very hot (30 Celsius degrees) and I had to stop in Guttanen for refreshing myself. There's some traffic and due to the straight road, cars run very fast: luckily the tunnels are well lighted. The landscape improves approaching Handegg and its waterfalls (what a pity: they're almost dried). A long and wide bend on the left takes you into the last 10 kms. quite demanding both beacuse you already are on the climb from 17 km. and because during last 10 Km the average slope is > 7% and there are two flat stretches ... After an harpin on the right you meet a tunnel (slope > 11%) that bicycles avoid on the right with a nice route (100 mt. are on pave') coasting some gorge that free climbers use for their training. You see the dam of first lake and you know you'll have to go up there: a set of bends help you on gaining altitude and finally you coast the lake at your right with its peculiar colour. Use the stretch along the lake to rest and don't be deceived by the the fact that you clearly see the pass not so far.
The stretch till the dam of Grimselsee is demanding as well: if you want to go to the Grimsel Hospiz (that nowadays looks like a true hotel) turn right on the dam and you have still to climb a bit in order to reach it. Also along the Grimselsee the route is flat and you can look a bit astonished at the colour of this lake green and grey (but it's not dirty water: it just comes from Grimselgletscher).
The last stretch to the pass (length 3 km; remember that from Innertkirchen to Grimselpass there are more than 26 km and not 25 as quoted in many books) is made up of harpins and the average slope is > 8% and till the end hard work is required. (till here: 122 km. 450 min. 3100 mt. of devilement). Unlickily I'm too tired to face the climb to Oberaarsee and also worried about missing the train that from Briga will take me to Italy. It's the third time I reach Grimselpass and due to bad weather or tiredness and/or lack of time I've never managed to face this climb starting from Grimselpass that according to descriptions takes you to a new lake with beautiful views. (never mind: I'll have to come back another time). The descent to Brig is well known: very funny the first part to Gletsch and also the one to Oberwald (except a short pave' stretch near a rock tunnel: beware of that). From Oberwald to Munster there is also a short climb: I face it slowly because I'm short of energy. From Munster to Brig it's almost definitively descent: there are only some stretch lightly climbing up (at his point of the trip you notice the slightest slope) and the landsacpe become anonymous: luckily Brig shows up suddenly and the rail station is easily retrievable. (till here 170 km. 550 min. 3200 mt. of devilement)
If you think of this trip as too long you can come back to Kandersteg in order to take the train to Brig: in this case the second climb of the day could be the one from Spiez to Kandersteg that is the last stretch of 4th stage of 1997 Tour de Suisse, La Chaux-de-Fonds Kandersteg, won by J. Ulrich and you can shorten it by taking the train to Brig in Frutigen instead of Kandersteg.