The simplest way to quickly check this is to check the owners manual on the towing vehicle for its towing limit. If you can't find it there, call your dealer and they should be able to tell you.
If they can't help you, the search for it on the web.
Once you have this number, remember that this is a MAXIMUM limit and it is usually recommended to only tow a tow vehicle that has a GVWR of 80% of this number. The GVWR is the Gross Vehicle Weight Rating and includes the gear a typical camper will have in it.
I would suspect that unless your RAV4 has been specially equipped, it will have a towing limit of only 3000 lbs, or possibly as low as 2500 lbs. But check to make sure, and make sure you get the appropriate towing accessories such as; tow adapter, ball hitch, safety tow cables, tow electric cable, and possible anti-sway bars.