On Wednesday, August 9, 2017 at 7:07:34 PM UTC-4, wrote:
I'm a new glider pilot looking at purchasing a 1-26.

I'm looking at gaining the flights and experience to get the Commercial Glider and adding the CFI-G to my existing CFI-A.

I envision doing auto tows at my local 3200ft airport. I'll hopefully be getting to 600AGL to just do laps around the pattern. I'd plan to use a 1000ft rope and my 8.1L Chevy Suburban.

What's everyone's take on auto towing a 1-26 mostly just for the fun of very quick flights? Do I need a logbook endorcement for ground launching?

You do need ground launch training and the associated endorsement.
To ground launch with a reasonable degree of success, the glider will need a CG type hook. Some A/B/C's had such hooks. I've never seen an E with one.
It is not likely you will get 600 feet with 1000 feet of rope on a nose hook.
It sounds like you are trying to do this on the cheap. May be false economy.
FWIW
UH