I'm not well-versed on apps, but can perhaps offer a little general advice:
In my experience, hotel gyms don't have much in way of stuff for heavy lifting, so squatting a 3RM or busting out some heavy deadlifts is often not going to be possible.
However, if you're just trying to get in shape then you don't necessarily need a lot of kit. All gyms generally have the equipment necessary to do some interval training in the form of a weights circuit or complex.
So just pick like 4 exercises you can do and do them all in one go without resting. Once you've done all 4 (or whatever number of exercises you choose) you would rest.
Circuits/complexes are brutal, and you can absolutely destroy yourself with not very much weight or equipment at all. Really, a single set of dumbbells would be all you'd need (but of course you can use a bar, various machines, etc).
It's not going to build muscle like lifting heavy weights will, and it'll not drive your numbers on the big 3 up, but it'll absolutely get you in shape.
Hope that helps!