Cross Country Trip

Hello all,
I have been a BMW MOA member for several years as well as an airhead member. I am moving from Boston to San Francisco this summer and riding my three bikes cross country with two friends in August. I would like some advice on a towing service (for piece of mind and as a last resort) which I could rely on during this trip should it come to that. Any thoughts?
Also, any other tips would be greatly appreciated!

haulbike.com

Used this company from VA to OR this summer and was very pleased.

https://www.haulbikes.com/zonemap.html

Are the three bikes BMW's ?

If one of your three bikes fails to proceed along the way you can always try finding help using the Anonymous book. Or, if that doesn't work, rent a van, load it up and haul it. A storage rental can be a good place to stash a non-runner. Your friends could ride two up to finish the trip with a return to recover or a pickup and transport by 'haulbikes' within the first 30 days. These are things mentioned by people over the years at rally time from having been left a-foot and lived to tell about it in the MOA news...and elsewhere. But, you are going to have a nice safe relaxing and enjoyable trip across the US.

Boston to San Francisco.........Perhaps you should start your ride somewhere along the eastern shore. Sea to shining sea and all that sort of thing.

Thanks for the recommendations! I do have the annonymous book and was definetly going to take it with me.
Two of the three are beemers. A 1970 R75/5 and a 1972 R75/5. I've done a lot of work on them in the past but had Max BMW in NH give them a very thorough tune up this past winter as they are getting up there in years! I am really looking forward to the "sea to shining sea" adventure. I live in downtown Boston so starting at the Atlantic Ocean is easy. We'll be riding straight to the SF Bay! Planning to go through South Dakota, Wyoming, Idah, Utah, NV on the way.