If the tires are old, definitely consider replacing them, if you'll be traveling at all you'll need to invest in tires anyway, might as well do it now.
Wheel Bearings - be prepared to repack the bearings, - bring grease, cotter pins, and tools (jack, stands, wrenches, pliers etc)
Brakes - best way is to replace the complete backing plates if necessary - I'd look in advance for a trailer shop or trailer supply place near where you'll be picking up the trailer in case you need to buy parts.
Wiring and lights - the plug on my '77 was wired differently than my truck - i think the standard changed some time in the late 70's. I had to replace the umbilical cord anyway and rewired it to match my truck. - your tow vehicle has a brake controller right?
Hitch - be prepared to spend some time setting up your hitch, most hitches have lots of adjustments for height, weight distribution and sway control. it's not as simple as hitching up a small utility trailer.
Good luck, hope everything goes well!
1977 Safari Land Yacht
2005 Toyota Tundra SR5
2010 Ford Flex Ecoboost