The bottom one is a great route, be carefull of weather though, last time I was there it was early June but lots of rain futher south and the Rhein floods quite often then the road along side is unuseable there is a lot of up and over hills rather than skirting round the bottom of them, interesting riding but doubles your time at least.
Rudesheim is worth a visit, and a stay they have a good campsite near the river and there is a ferry crossing there to get from one side to the other, I have stayed there a few times and use the
https://www.hotelrose-online.de great little guest house, very good off road parking opposite the entrance, all CCTV and last time I was there the prices were very reasonable, and a good breakfast. The old Asbach distillery is there to, dont make it there anymore but the visitor centre is worth a stop, so is the Brandy.
With the first route it takes you not far from the old Bridge at Remargen, great stop for brits who remember the film, but never seems to appear as a stop on any of the routes in German bike mags, but worth a vist, nice little museum