if there's an army Surplus store in your area, they usually have gun bore brushes that will get some of that water corrosion out of the tubes... Ebay usually has some options too.

Penetrating oil after an initial cleanout will help too. I use a wire wheel on a bench grinder for external corrosion... The Internal corrosion can also be removed using a Flapper made from a steel rod, cutting a slit in one end, then slipping a foot or so of Emery Cloth into the slit... roll it up the right direction, slip it inside the fork tube or lower tube, and CAREFULLY spin it with a variable speed drill motor... check progress frequently, and don't Over-Clean..

You're beginning to see why i mentioned just getting a different fork, and getting help from a shop.... That said.. go for it, you're half way there... And the tools will come in handy in the future.

The hex screws will be the easy parts. 5mm hex socket in the screws, right? Ace Hardware, etc. has an amazing collection of such things. the THREAD size is most likely 6x1mm. I recommend Stainless steel replacements... no rust that way. The Grease used in these forks is a Rock Shox Grease called "Judy Butter"..Ebay or a bike shop should have it... Coat the elastomers and parts lightly, Do NOT Overfill the forks with grease. Other greases may end up turning those super rare Elastomers into sticky Goo.. Lithium Grease is Specifically Mentioned to Not Be Used by Rock Shox. any seals will need a light coat of Judy Butter too...

The forks got water in them because of bad seals and neglect (leaving the bike outside in the rain)and/or pressure washing it.