Things I brought and actually used on our 1st long trip (13,700 mi):
1. Tire changer ramp - worked great and used it our 2nd night out!
2. Torque wrench for lug nut checking
3. Spare hitch pins, clamps, etc for our Equalizer hitch and Milenco mirrors. Basicslly ANY spare small parts that are used / removed and that can be broken or lost. I made a good friend in Nova Scotia when I had a spare clip for his hitch.
4. Head lamp in addition to a flashlight. Keeps hands free for working or going to restrioms in the dark.
5. Pipe thread sealant or tape for propane tank connectors.
6. Small Weber Go Anywhere grill (gas).
7. A quality tire pressure gauge. All the various opinions notwithstanding, most tire failures are due to failure to maintain correct tire pressures.
8. Heavy socks or slippers - trailer floors are cool!
9. Large quick dry camping towels dry much faster than usual cotton towels and take much less space/weight.
10. Rolls of quarters for laundry and shower facilities.
11. Cheap shower cap (free from most hotels) to place over smoke alarm to be used ONLY WHILE ACTUALLY PRESENT AND ACTIVELY COOKING. Regular toast always sets ours off.
12. Bungee to hold power cord in place on pedestal - many are worn and loose.
13. Noncontact tester snd volt meter. See this site: RV Electrical Safety: Part IV â€“ Hot Skin | No~Shock~Zone
. We found 3 sites in 3 months needing immediate repair for major safety problems.
14. Locks for anything you want to keep and leave connected for a few hours while you are away from your trailer. No one bothers your sewer connection, but everything else is vulnerable. Not all trailering people are as nice as those on this forum.
15. A well stocked (and regularly restocked) first aide kit appropriate to your level of first aide training and with OTC meds relevant to your unique potential medical needs. Insect repellent.
16. Real maps - makes planning the next day much easier than a GPS. AAA is our preferred source.
17. Good trailer breakdown coverage from your preferred vendor, also memberships save money at campgrounds. This is highly individualized, but both are well worth the cost. We did not need the tow coverage, but our traveling companions needed a tow for 250 miles (twice) and saved a lot of money using AAA with rv coverage.
18. I second spare keys OUTSIDE the AS and bourbon inside the trailer (in Newfoundland we had to have "Screech").
As others have said, WalMart is probably the most frequent place we check when a need arises.