Hauling toys, Motorhome, Towable, or Lift?
Five people will pretty much fill a full size Class A on such a long trip, so I'd trailer the bikes behind the motorhome. Anything else will be a serious cramming of people into too small of a space for all those endless road miles.
That's my perception based on a couple of three month, 7000 mile trips with just the wife and I in a Class A. The idea of adding three more people while simultaneously reducing the living area in such a drastic way, and I'd cancel that trip in a heartbeat.
If you guys really love toughing it out while being packed together them try it with less living space square footage. Maybe you could just pretend that you're all canned sardines for the trip.
Again you asked for opinions, so I'm just giving mine, Class A and a bike/equipment trailer required if enjoying the trip is one of the goals.
Joseph and Sandy
(Snowbirds in Reverse)
Winnebago Chieftain / Ford Hybrid Toad