Standard advice:

Something that fits in your budget of course. Leave reserve for some instruments, insurance, andoney to buy tows.

Make sure you fit comfortably. You'll be wanting to sit in the seat for 5-8 hrs.

Automatic control hookups are a deciding factor for many. Decide if it is for you.

That will narrow it down to maybe a half dozen types. From there, find what's available at the price you like, and pick the one with the nicest trailer.