Training for hills where there aren't any

Now that I'm living in a very flat city, I'm finding it a challenge to prepare for vacation rides that involve climbs. My husband and I want to go back to our old stomping grounds to ride a mountain pass that's closed to cars until mid-June, but how to prepare for the 38k of gradual climbing (one side) or 17k of short-but-steeper climbing (the other side)? We've found a hilly loop going around an exclusive acreage neighborhood, but the residents start giving us funny looks after about 3 laps. ("Look Fred, those middle-aged lycra-clad burglars are casing the neighborhood again. Lock up the silver!")
There is a lot of wind here - nothing to stop it as it sweeps across the prairie. Has anyone ever used a fierce headwind as a substitute for hills?

 

A head wind is good. So is a stationary trainer.

My goal would be to do prolonged low cadence, high power efforts.

Colorado has several climbs that I do on vacation - 200+watts, 70-80rpm for an hour or so. I try to replicate those into head winds or on my trainer.