that setup should be fine for those basic uses...
I run a very similar setup. I have a Dell Inspiron 8000 (650MHz P3 with 384MB RAM) in a docking station in my trunk. I have Windows XP on it, I use it for GPS (iGuidance4.0), Videos, Music, Internet, OBDII, etc.
It all runs fine on my old laptop. I don't use a front end so I'm not sure how much of a resource-hog RR is, but your P3 is 250MHz faster than mine, so it should be fine.