Its pretty straight forward mate...but its been my full time proffesion for years :S so i will think that lol
Not much you can do with the forks if the legs are rusted! Use GT85 or TF2, spay them on the forks legs and try and compress the forks...
With the brakes, if they feel seized it will be the cables, u will need to replace the inner and outer cables which at my shop its £3.99 for 1 brake and u need to cut down to lenth, that goes for the gears aswell!
As Neil NA said replacing the chain can become rather costly! its very rare the chainset (which is the front cogs) will need replacing when changing the chain but the casset will.
Shimano chains from us start at £17.99 and the casset £12.99
With a shop to do the work labour would have to be paid. If the bike came to me id advice a standard service which would cost £41 inc VAT then that would cover all your labour costs of what we would do... just have to pay parts ontop!
If you need any more help mate PM me and i can advise
Paul