You'll be fine running it out of a window. That's basically what I did, except I've skinned all my windows so it just goes up from the stove, 90s and then goes out the wall, another 90 and then up over the ridge line of the bus.
I've never had a problem with draft. I get good complete burns with seasoned wood and haven't ever had a puff-back situation. Make sure wherever you go through (window or ceiling) you use double or triple wall pipe. There are pics in my build thread.
When on the road I just pull the pipe going through the wall and external chimney, cap the hole and cap the stove and I'm off like a prom dress...