I've had 2 Dahons, one Dahon for about 5 years as a commuter before I decided to upgrade and get something new (Tern Link a7) and I tell you what... I miss the Dahon. Great build quality, got dropped down the office stairs once, didn't leave a dent. Nothing Dahon-made on the bike broke (Hinges etc) but eventually it ended up completely worn out and costwise, not much more to buy a new bike so I went in for something new on the market. Regret it. I'm starting to get on with the Tern, but I certainly wouldn't trust it in a suitcase on a plane. I'd constantly worry it was going to break somewhere. The Dahon, I'd throw in there myself with a case, no problem
But yeah, a cheap Dahon would be suffice for what you're doing ,with a few luggage bags. I had a full triple pannier with a sleeping bag/tent/travelling stool on my Dahon for a small tour once, didn't effect the bike whatsoever. Brilliant little thing.