Look at the pipes closely. One of them commonly gets it's moisture drain hole plugged by "chain fling" and subsequently rusts out from the inside. The reason I mention exhaust is it is probably the most expensive part to get replaced and can cost around $1,000 (unless you go aftermarket). I just got lucky enough to get a set of HM341's for $700.
Even if the engine is bad (probably not), you can get one for between $100 and $200. If it needs paint, sidecovers and tank work, you're still under the cost of a set of pipes.
If I was spending $1800, I'd want to be pretty sure the pipes were gonna give me at least a few years.
Having said all that, '72 is probably among the most desirable years (from my perspective)... especially if it is an early '72. If it was well maintained, 34K is not a real lot of miles but there are lower mileage bikes out there that might not be as cosmetically good as what you're talking about for less money.
If it has bitten you, try to get it for less money. If it has bitten you hard, just fork over the cash
If you don't mind working on a bike, you might consider getting one in rougher condition and "rebuilding" it. I'm not sure about other folks here (I could make my guesses) but much of my enjoyment comes from working on these ole gals.