First thing to consider is that if you do not have a toad, you will have to drive the C to each viewing area. Some parking lots at roadside viewing sites just do not have the room to park a C of much size. Plus the matter of having to unhook from your RV site each time you want to go somewhere. I don't know if you can rent a toad along with the C rental or not.
As far as flying into one city and out of another, it is certainly worth consideration. We have not done that with an RV rental, but have done it several times with rent cars. Have flown into one city, got a rent car, drove hundreds of miles, dropped off the rent car in another city, and flew from there back home. Saves backtracking a lot of miles and time to go back to the start. Doing that with an RV may be a little harder to arrange, although I think national RV rental chains will do that. If so, you could probably squeeze in an extra one or two of those destinations in the same time frame.
