Here are some things I would do:
1) Cycle the receiver and transmitter batteries several times to be sure they are ok.
2) Seriously consider sending the radio to a service center to be checked out. This will be cheaper than losing/crashing a plane due to a hidden problem.
3) Remove the engine and pull the carb and back plate. Look inside for signs of dirt or rust. If there are, consider buying new bearings. Clean the carb with alcohol and lube it before you reinstall it. Be sure to remove the needle and run a little alcohol or fuel through the spray bar assembly.
4) Thoroughly bench test all the servos. And then test them again with the engine running.
5) Carefully check all the hinge lines to be sure they are tight and that none of the hinges are broken. If any are suspect, remove the entire control surface and rehinge it. If any of them have excessive gaps, consider sealing the hinge line or rehinging.
6) Epoxy will work fine for fuel proofing small sections of bare wood.
7) Remove the fuel tank. Disassemble it so you can install a new clunk line. Flush it with alcohol. If the stopper is not still flexible, replace it or the whole tank. When you reinstall it, use new fuel lines.
8) If it came with a prop, you probably should replace it.
9) Confirm that all screws, nuts, bolts, etc are tight. Confirm that fasteners subject to falling off due to vibration (such as wheel collar set screws) were installed with Loctite.
10) Check covering seams and iron down any that are loose.
11) Check the tail surfaces to be sure they are not loose.

I'm sure there are other things, but that's all I can think of off the top of my head.