Bicycle Mechanics - Bike fit -- long stem and seatpost

There is a bike on craigslist that I would really like to get. The problem is that it is a little too small. I'm 6'2" and have a 35 inch inseam, and this bike has a 58cm frame. I would be using the bike for loaded touring, so if I were to put an extra long stem and seatpost on the bike, would the handling of the bike be affected by a lot? Are there any other problems with this idea?

I wouldn't do it. In addition to affecting the steering, you also have to worry about heel strike on your panniers if you are doing loaded touring.

What brand is the bike for sale and how was the 58cm measured? If it was measured c-c that could be equal to 60cm or more in another brand.
But it does sound too small for you.

It depends on what 58cm means, your body characteristics, preferences, etc. How do you feel about the saddle-to-handlebar drop? My gut says it's too small if you're already worried it's too small, especially for touring.

I'm 6'2" with a 35" inseam and I ride a 58cm bike for loaded touring. My handlebars are barely below my saddle.

I am 6'2 and have a 32" inseam and ride a 58cm bike - a surly steam roller.
I subscribe to the Rivendell (old) school of thought - "a fistfull of seat post" is all that is necessary.

http://www.rivbike.com/article/bike_fit/choosing_a_frame_size

You would have to see the bike to know if it is likely that you can *easily* get it to fit.

I would reccomend bringing your allen keys and wrenches to see the bike, adjust the seat height and sit on the bike. If the bike feels very short or the bars feel verylow then you should not get it... but if the bars seem close enough to where you would want them without getting a crazy 160mm stem or something.

I suspect that because you are planning on loaded touring that you will be spending many hours in the saddle, and this will make an odd fitting bike seem much much worse.