The altitudes vary from 3k up to 10k, depending on the project, and while there are tolerances to fly to, they're pretty manageable. I like to say that if you can fly a LOC, or fly straight and level period, you can fly survey. Picture it as driving a Zamboni in the sky.

I'm at 78 hours this month with another half to go...

You can rent my skyhawk for cheap and fly the sh*t out of it :D

Jump pilot is a way to build time. Try a place that operates year round. You can start in a single engine piston, get experience and prove that you can fly safely and efficiently, and jump in a turbine once someone leaves which will be pretty quickly. Pay is ok to decent but it's long hours (think 8+ hours in the plane) on busy days and sitting around for hours on slow days. I logged 17 hours last weekend and about 14 this weekend plus 8-30 during the weekdays.

I fly for a Part 135 company as an SIC. Flew 104 hours last month and still had 9 days off. Home every day too.