JC, get you a good, small portable tool box. Look over the bike and see what you feel comfortable working on while on the road and carry those tools in the box. A good, compact air compressor is a must along with tire plugs and a small can of fix-o-flat (fix-o-flat is the last ditch option). Extra set of spark plugs, a couple quarts of oil, extra headlight/tail light/turn signal bulbs if you aren't running LED's; tie wraps in various sizes, small can of WD-40, roll of shop paper towels, small bottle of waterless hand cleaner, a zip-lock bag with $100 and a pre-paid Visa....a must!
Again, carry things you feel you can use to work on the bike at the road side/rest area/hotel parking lot. You can get most of these items in the tool box which can sit in the front (toward the tongue) of the trailer and pack around it. It really doesn't take up that much room.
I was the pack mule on trips so I carried the tool items along with enough maintenance items for two/three bikes. Still had plenty of room for clothes bags (ours and the other bike(s) ) with room to spare.