grosse scheidegg/swiss bike route #4 questions

Hello,
I am contemplating a 5 day trip to Switzerland next week. I have never
biked in Switzerland before, and hence thought I would stick with the
national bike routes--in paricular, bike route #4. See:

http://www.myswitzerland.com/en/navp...onalRoute.html

After browsing this NG and talking to some friends, I think I would
like to skip one of the daily segments--the Thun-Fluelen one--and
instead take the train from Thun to Lauterbrunnen, and bike from there
to Grindelwald, climb Grosse Scheidegg and then end up in Meiringen. I
would then take a train to rejoin route #4.

I've read Jobst Brandt's reports, which seem to indicate that there is
a paved road accessible to road bikes from Grindelwald over Scheidegg
and into Rosenlaui. I wanted to double check with the group to make
sure I was interpreting this correctly, as my Swiss map (Michelin 551)
indicates what appears to be an unpaved track, not a real road. I would
hate to get to Grindelwald and find out that's it's all gravel or
closed or whatever!

Also, any general comments from anyone who has familiarity with route
#4, or the Swiss regions it cuts through, would be greatly appreciated.
I am doing "credit card touring" on my road bike, and will be staying
in B&B's along the way. Will I need to worry about trains being too
full to accept more bikes? Advice on roads to avoid, sights not to be
missed, things to pack, etc.?

Thanks!
Vincent.