Hi Fearless,
Since JohnB brought up the project I might as well chime in. We got the airplane as a structurally complete but mostly gutted project in December, 2011 and really started restoring it November, 2012. We've worked through the center section, fuselage, tail feathers, landing gear, flight deck, cabin and are now working on FWF and the outer wing panels.
To answer your question, what kmiles said is pretty accurate. There are a few Goose-specific type parts that have taken some real scrounging to source but once the airplane is flying I think it will be fairly easy to maintain/operate. The airplane is really very simple and EXTREMELY well built. I've been involved in many projects from probably 6-8 different manufacturers, and Grumman tops the list IMHO for design quality. Anyway, the flaps are vacuum, the gear is hand crank (or, can be modified to use an electric "booster" motor but that is just a generic Y-150), the flight controls are simple cables and push-pull tubes. The wheels and breaks can be a variable. There is an STC for Cleveland wheels and breaks which should make the maintenance/operation pretty nice. The parts for that conversion are available but extremely expensive (I think a full wheel/break kit for the airplane is something like $50,000. We would like to replace just half of one wheel and have had several people turn down $4000 offers!

). Obviously the 985 is bullet-proof and very well supported.
The "gotcha's" I can think of right now:
1) It has two fuel tanks, 110 gal each in the center section. It is pretty standard "wet wing" tanks, but if this is old you'll have fuel leaks just like any old wet-wing airplane. The center section is pretty complicated and very "beefy" so if you need to do ANYTHING there, including maintaining fuel tanks, you'll be in for a big job.
2) We have had some trouble sourcing the elevator and rudder trim parts. There is a gear box driving a flex cable drive, which runs a drum, which turns cables to the back of the airplane, wound around another drum, driving another flex drive cable, which then drives another little gearbox/jack screw which actuates the tabs. The gearboxes, flex drive cables and drums have all been difficult for us to find (although now we've got everything we need). These aren't really common parts to need, but I'd guess there are several Gooses out there that have one or more of these components worn and needing replaced.
3) Like I said, the wheels and brakes are very expensive. The old original brakes are probably cheaper to maintain, but would require more scrounging and they just generally really suck...
4) There seems to be two generations of exhaust collectors. The earlier one is pretty maintenance intensive (I'm told). You can have a brand new collector set built up by Acorn if you've got big pockets but there is SOME good condition, original, late style exhaust stuff out there. Just something to keep in the back of your head.
That's what I know. Big picture, there are 4-7 active Goose restorations going on right now (including us, depending on how you count) so there is support and knowledge for the airplane out there. Pacific Coastal in Port Hardy, BC still operates 2-4 Gooses at any given time and they have pretty good parts inventory (although their main goal is to keep their airplanes flying, not make money selling Goose parts). Like kmiles said, I think the airplane will be a blast. Basically a Beech 18 (very fun in it's own right) but amphibious, and BETTER!

Check out our Goose restoration gallery on our Facebook page (public page so you don't have to be on FB to see it) for some drool material:
https://www.facebook.com/media/set/?set=a.10151116963488785.440136.187204493784&type=3