Sounds like a plan. I would think about the coupling caps because, if they get leaky, they can red plate the output tube and or burn up an IF coil or OPT which are pretty much unobtanium. For the philco bakelite blocks, they are really a piece of cake. The blocks can usually be retrofitted with new cap or caps without removing them from the radio if you have a heat gun and some aluminum foil.
There is a guy named Chuck Schwark that can provide factory documentation for Philco radios. You get a nice large schematic in the mail plus parts list, and any production changes. Philco uses some non standard color codes on their resistors which make a schematic a necessity. These colors were designed to be more visible under the mercury vapor lights used in the 1930's. About $7 for a table radio. A little more for the big twenty tube consoles.
SSTRANS makes a really nice SS AM transmitter kit - the 3000 - the 5000 is also nice, real nice, but $$$$.
Or you can build one of these for a few dollars.
It takes the audio and drives the VCC pin of a 1 MHz crystal oscillator - voila amplitude modulation. It works surprisingly well.
There is a guy that sells a nice tube AM transmitter on ebay for a couple of hundred but I personally have never used it. Just mentioned it because some people are allergic to sand.
I, of course, have no affiliation with any of the products mentioned in this post.