Farm & Fleet generally has a Mobil 1 sale, in various viscosity grades, at some time of the year, and possibly coupled with a rebate. This makes for a very good $$$ deal!
Many guys are running Mystik JT- 4 2-cycle Full Synthetic, or Amsoil Interceptor. Mystik JT 4 2-Cycle Full Synthetic is around $28 @ Farm&Fleet. When on sale, with the rebate, it's around $20. Very good oil, top of the line specs, cold flow, and viscosity levels.
I use the right size, and load rated trailer tires for the load, plus trailer weight, and gear loaded in the trailer. I then will adjust tire pressure, up, or down, in order to get the proper wear. This has always worked well for us.