An RV is more like driving a car/truck. Usually just 4 wheels and it goes where it should. Towing a trailer means turning corners differently or you'll be up and over the curb - and the light pole - in a split second. Getting gas means you plan your exit strategy before you pull in. Most likely the RV you drove did not have the length that your Tahoe + a trailer will have. Backing up is a challenge....or not, but it's totally different than backing an RV. Having driven an RV, you know that you'll need mirrors that let you see at least partially behind you...the standard ones on your Tahoe are likely not going to do that. WDH with sway is an important part of towing safely and it's more than just a quick snap to hook up and unhook, so you need to have a lesson in doing that.
I don't mean to discourage you, but towing is more than just getting into the vehicle and heading out. Just want you to be safe and have a great trip - not one you're sorry you ever got involved with. You need some advance planning. Strongly suggest you check with the rental company and find out about some time to go over exactly what you'll be getting and time to learn how to use it.