Sorry to be slow answering. I think on a Pleasure Drive, the things you meet will be pretty easy to deal with. No one expects you to be racing along, making things into technical hazards to drive thru. It does sound like a lot, in only a bit over a half mile! But maybe they give you points for every gate you go thru, passing by decorative items, etc. We have done pleasure drives like that, things you might meet on a road. Laundry on a line, person with a bike, bales to drive between, many ideas out there.
You can call the Show contact and ask about what type “gates” to expect on the Drive. Check the ADS Rulebook for details, there used to be timed Pleasure Drives. Always good to know the Rules! Like a Hunt Pace, not too fast or slow. Supposed to be elegant!
I would definately enter the class just for fun. I love anything out of the ring! Good for the equine to see new stuff too or maybe old stuff they already know, in a new location.
I agree with DMK, go with VSE or ponies, so your pony is not up against horses in the class. Have a good time!