Poor Planning.

OK, So I brewed 3 batches during the past several weekends. Two of them got kegged this past weekend. I only have 2 kegs right now. The 3rd batch should be ready this weekend (3rd week in primary).
The problems is: I don't want to bottle this batch (spoiled by kegs) and I don't want to rush through one of my kegs just to free it up. So my plan was to rack this batch into a secondary carboy and leave it sit for like 3 or 4 more weeks until a keg gets emptied. I may even use that technique on here about bottling from a keg to help empty one of them.

The batch is The Innkeeper from Northern Brewer so it's a lighter kind of beer. Will it be OK sitting for an additional 3 or 4 weeks?

Also, how long does beer stay good in a keg? I've had a homebrew that was over a year old in bottles and it was still really good. Not that I want to tie up a keg that long, but I was just wondering if there was some kind of age guideline.

you'll be fine letting your other batch sit in the secondary for another 3 or 4 weeks.

My batches typically don't get into a keg until a month after brew day, and sometimes as long as 2 months after brew day.

As for the longevity of the beers in a keg... as long as you sanitize and transfer carefully and properly, it will keep (meaning "not spoil" for a very very very long time).

Agressively hoppy beers tend to lose some of their hop character. but the beer will still be drinkable.

I would say that you don't even NEED to move to a secondary. It will keep just fine for a couple more weeks in the primary.

Then again, if you practice good sanitation, then there is nothing wrong with a secondary either, other than the bit of work of actually transferring the beer.