No need for a spare hub if you have done proper maintenance! I have done this trip twice a year, down and back for almost 10 years and never took a spare hub. Bearings fail for a couple of reasons, lack of grease caused from bad seals, rust from water intrusion, or improper adjustment. Check the back of the hub to insure no grease splatter(bad seals}, jack up a wheel, spin to make sure it is smooth and silent, i.e. no grinding noise! Grab the wheel and check for excessive freeplay. If you have to ask what excessive freeplay is take it to a mechanic! Oil bath hubs are very dependable, as long as the seal has not been compromised. If the oil looks milky you have a problem with the seals and they need service.
I39 through IL is now 65 mph pulling a trailer, the toll road is still 55mph. By taking I39 you bypass Chicago, Indy and Louieville, but get to drive about 50 miles further, the fifty miles is worth it!
What you do when you get to FL and before you leave is important. Before getting the hubs wet, make sure the hubs are cooled down from the long trip. Don't launch the boat until this is done. The warm hubs hitting the cooler water will cause water to get sucked in through the seals otherwise. Before you leave, check the sight hole on the hubs to make sure the oil is not milky. Grease any zerk fittings on the steering tube , and lower unit on the motor before leaving, also run the tilt and trim up and down a couple of times after lubing and then lube again, will push any salt water out! Don't forget to check your air pressure on tires also.
I check hubs after about 50-70 miles for heat, if they aren't hot by then you will be good to go for the rest of the trip. I check them when filling up with gas after that.
3400 miles round trip, fishing Mangroves...sounds like you are going to the west coast, probably between Venice and Ft Myers? Englewood? If so, some great fishing and boating, have fun!!!! Nothing better then fishing salt water.
