fender guitar with amp

is a good idea for my guitar amp microphone (a small fender valve) to listen on a Stagepas 300 PA?
Ok i just to sell one horrible 4×12 cabinet and head (two defenders also solid state) and I love my little practice amp tone, is a state of the valve, so I want to keep that sound, i even heard drumming and playing bass at the same time (no problem with that). The thing is I want to be able to listen to my power noise, and add some piano, so a guitar amplifier can not be done, and I have only about $ 550, so I was tihnking that the PA buying micing guitar, electric sound and the creation of a keyboard directly through the mixer. Any ideas? Is this a good idea? will to sound bad? HEEELLLPPP !!!!!!!!!!!
Trying to mic the guitar can be a problem. You would be nice if you could connect directly to to the mixer. Or will encounter feedback problems.
Fender Hotrod Deluxe guitar amp review – Part 2 with Gibson Les Paul Custom