I prefer to put my bike(s) in the back. I fold down the left side, remove the front wheel, and lean the bike over on the edge of the upright right side.
I have a 56cm lightweight road bike, so if you have one taller, you may have to lean it more, fold down both sides, or take off both wheels. A mountain bike may be tougher to stuff in there, but someone on this site has done it. If you don't have a spare tire, you can lower the cargo floor for a couple extra inches clearance.
I also purchased a set of cross-bars (Wispbar from Yakima) and a roof-top bike carrier, but I haven't had the need to use it yet. I have a plastic folding step stool to make it easier to get the bike on and off the roof when I use the bike carrier.
ditto. I normally carry mine in my truck but in bad weather I carry it inside my renegade. I have an 18" mtb with 27.5 wheels and all I have to do is drop back seat, pull the front wheel and seat post and it fits fine. you can leave the seat post on if you want to lay it over.