Pretty sure most vehicles will cut power to AC compressor under full throttle.
I never recharged my AC after my engine was rebuilt, and a few years after that I removed all its peripherals except the AC compressor which just acts like a pulley. thing does weigh 25+ lbs though and the pulley does not align perfectly with other pulleys.
Even when my AC worked, somewhat anemically, I never used it as I hated the throttle feel when it was robbing the engine of its power.
MPGs around town, well I've given up on them. Running traffic lights would be the best mpg improvement I could hope to achieve
On the highway, I try and drive at night outside any possibility of traffic, and drive 65 to 68mph. There is a MPG wall after that speed I've noticed.
The Van is a leaded barn door. heavy and unaerodynamic. Easiest thing to do is slow down, and keep a steady speed. With the added ride height, look 3 or 4 cars ahead of the one infront of you.
Who no doubt is checking and LOL'ing their instagram oblivious of their surroundings as they chant "me me me me me"