temp control in the toy hauler garage for kids

We just bought a new to us toy hauler this year (Raptor 310TS). It does NOT have a/c in garage. We used it during the hot months of summer and kept doors closed when we had dirt bikes/tools inside. Yes, it got hot. That said, we've it several times for sleeping and dinette. If we left door open and had a fan, it would cool it from the living area.

I'd get 3rd a/c if I were you. That should work great.
PS: We looked at both GD models you're looking at. They were our top choice for new.