The Dob would be an exellent option. But as Andy and Brent said, the smaller scope still has a lot of potential. my little 60mm refractor is still used more often than my 12" dob because it is smaller, lighter,easier to set up, and is not as sensitive to seeing as the dob so i can use it for a quick glimpse of the sky. ( I also don't have to break my back setting it up like the dob)
The 12" dob would have a lot more light gathering and resolving power than that of your current reflector, so DSO's will show details invisible to the smaller scope.
My 12" dob is a solid tube, but i can still safely transport it in the back of a stationwagon or 4WD (but i often lose a back seate), so transportation should't cause much of an issue considering it can collapse, but i can't make any promises because i've never tried it in a ute.
Hope this helps
