To trailer two good size bikes you will probably need a 8' wide trailer (width includes the trailer wheels). Not sure I would be comfortable towing a bike on a trailed backwards. If you do take most of the bike accessories off (in particular the screen if it has one). Strap at four point and I always tie the front wheel to the wheel chuck. If the trailer has a flat bed then also brace the rear wheels or strape the rear wheel to the rear tie down locations. You don't want to over compress the shocks and if you hit a good bump then the rear wheel can shift. Over time this shift could result in the bike laying down. Thus the reason to strap the rear wheel.

This last summer I trailered my bike and two kayaks up to Beech Mountain,NC. Everytime I stopped I did a complete walk around and rechecked and adjusted as necessary. The trailer I used was setup for 3 bikes. So I put my bike on the middle rail and the 2 kayaks on the outside rails. It took getting use to the width of the trailer, but I liked it because it was wide enough that I could see both wheels at all times in my side mirrors.

Tom

Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. Benjamin Franklin, US author, diplomat, inventor, physicist, politician, & printer (1706 - 1790)