engaging A/C compressor causes dash light to dim

my '87 4wd le van (which i've owned for 20 years) was converted to R-134 two years ago. A/C has not worked for at least one year. today i had A/C serviced and recharged (it had .31 lbs. in system). the air now works but when the compressor engages, the dashboard light that indicates that the rear hatch is unlocked (the only one that should be on), noticeably dims. the compressor is louder than i recall it being the last time the air was working. the tech told me his leak detector light indicated a small leak near the front of the compressor. i'm guessing i need to replace the compressor. my question is: will a 1,500 mile trip be possible before i do so? in other words, if the compressor does fail, can i just cut off the belt and finish my trip, albeit without A/C? any advice would be appreciated.