Hi Professorbob, thanks for the information. It is helpful to have some local knowledge. I decided to go on the west side of the lake, as you suggested. We will go inland at Tarquinia, up to Tuscania, then to Marta and around the lake probably stopping at Bolsema. We will then backtrack a little and head up to Acquapendente.
I will look on the map for the tunnel and maybe try to avoid. The tunnel does not show up on my map but I will look closer.
I have a question regarding the route along the coast to Civitavecchia. I was going to take the Via Aurelia, which is the SS1, based on someone else's ride, but it is a ride from several years ago. This is not the A12 which looks like the expressway. Are you saying that the SS1 is also not good? There are not many choices along the coast, but I can probably do some weaving and stay of the SS1 as much as possible.
Thanks again.