HI Bill
Welcome to the site.
I see you are in Vermont, Canada. if you and your friend are both new to modelling it may be helpful to try and find a local model club in your locality.
Do you have any pictures of the model and what's already installed?
At 30 years old the radio equipment is likely to be past its best so a modern 2.4Ghz set would be good. They come in 2 to 4 channel versions and for a single motor model boat the 2 channel are fine. With 2 motors you can use a single channel to control both so a 2 channel would work, you will need more if you want to control each motor seperately. You can buy complete sets with servos but a combo receiver /transmitter would be OK. You can buy single servos and the cheapest will be OK for a rudder. ESC's are now electronic and for your model size Mtronik offer a range in the UK and they have BEC so you won't need a receiver battery. Motors will depend on the space available for the motor and battery. NiMh batteries as used in model cars are available from 7.2volts at a range of amperages. To get the model to plane you need to keep the weight as light as possible and try to place the batteries towards the stern. For a 30" model two speed 400 motors should provide plenty of power and will be a lot lighter than the 550 or 600 motors.
Could be the motors and props installed are OK but they may be larger than modern equivalents.
Your first job should be to test the hull for leaks. Many 30 year old wooden model have sprung planks that will need reglueing.
Good luck and please ask if you need any further help.
Perhaps one of our other Canadian members will be able to advise you on where to source your supplies. 😀