Tools needed depend greatly on what you intend attempting and what level of hand skills do you have.
An example of this would be that some people can drill out pins with a cordless drill without harming bushings or alox scales. We mere mortals can get away with that sometimes but the cheapest big box hardware drill press will make all the difference.
Most of the tasks can be done with hand tools, even the above mentioned cordless drill could be replaced by an old "eggbeater" hand drill. In most cases power tools just make the job quicker and in some cases easier.
My bare minimums would be Cordless drill and bits; 2oz and 4oz pall-peen hammers; centre punch; pin punches; fine file; side cutters preferably flush cutting; a dolly/bucking bar/riveting block and a small bench vice, the clamp on type is plenty.
From there, the sky is the limit...