1964 Dart restoration start
I work on a 64 GT and have a few suggestions for the budget restorer of a driver. My comments are mostly specific to a 64 GT.
If you plan to keep the stainless double side molding you will need to replace the plastic clips. Instead of buying them for several dollars each (you need like 60) look up the molding clip for a 1980's era VW rabbit. They take a little finesse but work great. Most of the rest of the clips I have found pretty available. That stops a lot of rattles.
The chrome flakes off the dash and radio bezels. Having them professional re chromed is hard to prioritize and a big expense. Take them off and apart from the clear plastic gauge covers and paint them with chrome paint. It won't last forever. But, I bet you will be happy with the time and expense. One thing to remember is that those chrome- look paints will turn cloudy if you try to clear coat them. Us a plastic primer and then usually one coat.
While you have the dash cluster out unplug the main connector carefully and clean the pins and sockets. Get a good quality spray contact cleaner. Also clean the fuse contacts. Bad grounds cause all kind of problems. Also if you replace the dash bulbs don't increase the wattage. The extra heat melts the blue covers and warps the circuit board. Also clean or replace the foot switch for the high low beams.
If you have the intermittent brake light problem it is likely the turn signal switch. That is an expensive part but luckily available again, thanks Dan and Ray. Before you do that clean out all the sockets and consider soldering a ground wire on for each of the tail lights. In general clean connections before you replace. A dremel with a small wire brush is handy.
On things like the tail lights and headlight rings (and everything else) keep the old ones even if you find new ones. There are folks who can roll pretty bad wrinkles out of the lightweight metal of the headlight rings. Same on the tail lights, glue them wash them gently and they will look pretty good. The reproductions are just too expensive for me to enjoy on a driver. If you are missing only the center chrome ring on the tail lights an aftermarket stainless gauge bezel from a semi truck accessories site work great and look better than the plastic. Glue them on with hot glue or silicone in case you need to take them off.
Look on this site or other early abody sites for upgrading the electronic system and then put in a good ignition. Be careful about running a big stereo amp until you do an upgrade.
Last thing Remember new parts can be bad from the get go. Buy good parts and learn how to check things out before you just throw in new parts. A lot of very cheap parts fit these cars. You get what you pay for.