Feature-wise, there is not a huge difference between a P&S and a low-end DSLR if you leave the DSLR on Auto. The DSLR has much more options, but you don't have to learn them all to get good results. I think I kept my first DSLR on auto for 18 months before I started to explore its options further.

Usage-wise, there are at least two major differences that you should get comfortable with before your trip: composing with the optical viewfinder instead of the LCD and using the zoom ring on the lens instead of the zoom lever on the camera.

Most DSLRs have live view, which is similar to composing on a P&S but the optical viewfinder is typically the better option and you should get comfortable using it.

P&S cameras have motorized zooms that you operate with a lever on the camera body. DLSR lenses typically have zoom rings (some older lenses have a pump zoom that you push and pull) that you twist to achieve the focal length that you want. This is very intuitive but still different from a P&S.

While there are a lot of other differences, these are really the ones that stand out the most in learning to use a DSLR.

Size-wise, the P&S wins hands down. To get the real benefits of a DSLR, you need the body and at least two lenses, which weigh at least four times as much as the P&S. There is also the the process of changing lenses, which you need to be comfortable with (not that it is difficult). You can avoid these issues by getting an 18-200 mm or similar superzoom lens. A lens like this does not provide the best possible quality but it is very convenient (and the quality is still OK).

If you think learning these things and the loss of convenience are something you can live with, you are probably going to be very happy with a DSLR.

Personally, I'd make the switch in a heartbeat (but I am biased, I switched from a P&S to a DSLR seven years ago).

Cheers,
T.