While I haven't got an egg yet (wish I was as lucky as you!) There are a couple things I would be very careful of before the pull.
1. Get the trailer out in the open and look at the
tires. Cracked, checked, tread-worn? You may want to head to the nearest tire shop before hitting the freeway if you're going to need new ones soon anyway.
2. Light/brake connector - 7 pin? (electric brakes) 4 pin? (no brakes). Be sure you have the same hookups on your tow vehicle. If not, you will be going home without either
brakes or
lights, regardless of whether they work or not.
3.
Brakes. Check them before hitting the road. If your tow vehicle is rated for the trailer
weight, you may be able to stop the trailer without them working, but you will need to brake differently with a load behind you, and will need more space if the
brakes aren't working. In my case I would treat this the same as the tires. You'll need to get it fixed eventually, might as well schedule it in before hitting the highway.
4.
Lights. Bring spare bulbs. Bring a current tester. Bring some wire. Every trailer I have bought had wiring issues and lights that either didn't work, or worked wrong. Grounds in trailers are notorious for failing.
5. Coupler lock-down. I'll bet you fifty-bucks that the guy selling it doesn't have a pin to hold the coupler down and latched in place. $2.00 at a hardware store. Get a spare for when you drop yours and can't find it. Alternative solutions include a padlock, nut and bolt, or in an absolute emergency a length of wire.
6. Safety Chains. The ones on it may be the perfect length. Then again they may be old, rusted, and 2" too short. Bring a length of chain just in case. Put one of those "missing links" on it - the ones that screw shut since the seller will have lost his long ago.
7. Basic mechanics tools. bring a socket set and a toolbox with a handful of wrenches in it. Throw in a crowbar, vise grips, tire iron, and adjustable wrench. You shouldn't need these, but if you do...
Before you leave be prepared for one of 2 eventualities... seized brakes or seized wheel bearings. Most of the time as soon as you start moving the bearings and brakes will turn freely, but sometimes they can be beligerent. Be ready to take the wheels off and use a johnson bar to break the bond. If you have a helper along, ask them to watch th etires for a couple rotations and tell you if they aren't turning, or if they are making noises that sound unhealthy.
After about 10 minutes of driving, check how the bearings are doing. Just pull over and see if they feel hot. While having a seized bearing before leaving would be bad, having one seize up on the highway is worse. If you stop to have the tires/brakes fixed, you should really think about having them grease the bearings at the same time. Its an easy job you can do yourself later on, but for this first time, in unfamiliar territory, I would pay someone to do it.
Before pulling away, look inside the trailer for anything that hasn't been secured. Its easier to remove a teapot in one piece than 20.
More than likely most of this won't be a problem, but its better to go prepared than to find yourself on the side of the road getting a ticket for you non-functional lights while your wheels glow cherry red and the tires go flat.
Now this last item, I hope someone else chimes in on. I was reading a log of someone who rebuilt an egg. In removing the egg from the frame they found that the 2 main bolts that held the egg in place had rusted loose. All that was holding the camper was a handful of small screws. You may want to look under the trailer to see what is holding the FG portion onto the steel portion. As I said in the beginning, I have little experience with the FG trailers, so I can't give real insight, but I would be checking this before getting on the road.
I need to get a job driving for UPS so I can spot these deals...