Runs rough, carb cleanup / rebuild?

[mushinspace]

Hi.

I have a line on a '99 Nomad (53k miles) that has essentially been siting for the last 3 years. Current owner says that when he moved here, he didn't ride much, and the last few times he rode it, it ran rough and felt like it was "gasping" for fuel.

He moved from the CA area, so I'm almost wondering if it's a combination of gummed up carbs (from siting with old gas) and not being adjusted for altitude (mile high here in Denver!).

So, assuming he can get it started (dead battery) and running well enough that I can ride it home, would it make sense to try to drain the gas, fill up with new stuff, throw in some Seafoam and see what that does for it?

If the carbs are more gummed up than that, how hard is it to get to them and clean them out?

Also, what adjustments, if any, should be made for this thing to run properly here at altitude? My other bike needed adjusting when it came from sealevel (FL), and now it runs as well as it can, I think. Fortunately for me, that bike had relatively easy access to the carbs, so I didn't have to rip off the tank or actually remove them ... access via the outsides were easy from each side of the bike.

Suggestions and recommendations appreciated!

Thanks,
Sam