I'd love to poison first, and still might. I was just concerned about digging up the poison if I level everything before the gophers are dead. No idea how long I should wait.So.... what that picture shows is basically new mounds. I think I would start by applying poison first. Knock the critters down and THEN worry about leveling the land.
How about this. A controlled burn. Then either a heavy duty rototiller or heavy, heavy land plane grading scraper. Scarifiers down on the LPGS - just enough to bust up the surface crust.
I'm looking at the same job - later this year. Poison all the @#$% pocket gophers. Then level my one offended lawn with my LPGS behind my tractor. It's will be about a ONE acre project.
And yes, one attachment I've looked at is a land plane with scarifiers. I've figured about 50-60 miles of tractor time... per pass! The reason those grabbed my attention is because I thought I might could get it all in one pass if I threw a chain or rail road behind it.