Hi, I just went through a similar exercise, so let me share my experience.
I have Hawk on a Tundra double cab. The camper sticks out of the bed by maybe an inch, but doesn't extend past the tail lights...so pretty darn flush.
I bought a Rockymounts Backstage. This is a swing out rack which I figured would be rather handy with the door. I selected the Rockymounts because, in addition to being a bit less expensive than similar platform hitch racks, the integrated swing out means it extends a bit less from the truck which I believed would result in more clearance, ie. better departure angle, when traveling on rough roads.
When I got it home, I quickly discovered how half-baked all these plans are. Handlebars of mountain bikes do, indeed, contact (admittedly barely!) the back of the camper. I considered just padding this in some way, and, honestly, this might work, but I went ahead and bought an extension. Rockymounts 8 inch extension has their anti-wobble feature so I really wanted that, and wound up having to wait an extra couple of months because it was out of stock (Note: Rockymounts customer service has been perfect--they emailed me the moment it came in and helped me get it absolutely as soon as possible.)
As you probably know, most racks of this type have a tip down feature that tilts bikes away from a hatch back vehicle. The Backstage is no exception. Well, with the extra 8 inches, you don't really even need the swing out feature of the rack to open the door and access the camper. With the bikes tilted we can get in and out, swinging the door not exactly all the way, but with plenty of room. (I added some traction tape to bar extending from the receiver so we could use this area as a stair...worked very well) We actually preferred this tilt option sometimes on windy nights when the bikes might be swinging out there too much with the rack were folded out. And one time when, parked in a BLM campground it meant that the bikes weren't sticking a bit farther into the campground road next to us.
However, my brand new rack does, now, have some scuffs on the bottom after going over some dips and ditches which cause the rack to drag in the dirt. Trade-offs.
I hope this is helpful, feel free to ask me any questions--I have multiple different bikes on there at times, so I can address that, too. And also describe wobble performance, mounting, whatever. Pictures can be taken, just let me know!