Capacitors

Along with the tubes, there are 3 capacitors (10, 30 & 30) on the top of the chassis.  Being new at this, I'm going to try replacing all the capacitors, but my question is this, should I replace those three large caps with the small ones, and place them on the inside of the chassis?

If there is under chassis space, I would do the capacitor replacement rather the surgery to the old electrolytic. This usually means installing a terminal strip to support the transfer of the wires from the old capacitors. The old capacitor must be disconnected from the center terminals. Wires to the metal shell can remain. Sometimes the capacitors can be located elsewhere under the chassis. Don't locate them in the RF/OSC section.
Be very aware of polarity, paper sleeved metal electrolytics often have the metal shell above the chassis ground. Sometimes the multiple electrolytic has a reverse polarity or a negative connection but not to the shell. Look the schematic over carefully...

GL

Chas