I also see most people riding dh bikes WELL under their potential and only down green/trails.
Fixed it for you.
To the OP, it depends on what kind of trail bike you're riding. Current 140mm-160mm travel full-suspension bikes are surprisingly capable and would be fine riding a good majority of the trails at MCBP. The exceptions being really steep spots where the geometry wouldn't be ideal or the higher-speed technical trails where both the geometry and suspension limits would be in play. But, most of the park is totally rideable on a trailbike. Plus you're already comfortable on your own bike, so there's that.
While a DH bike isn't ideal for the smoother green trails, the geometry and suspension travel give you quite a bit more room for error when compared with a trailbike. It's overkill for some of the lighter, flatter trails up there, but overall it's the better tool for the job.
If you do want to rent a DH bike, I'd recommend making sure you get one that has some decent tread on the tires. As someone else mentioned the rentals can get beat up at this point. Tires are one of the most, if not the most important components on a bike. Especially for bike-park riding, especially if it's very wet or very dusty. Some days you'll luck out and get goldilocks trail conditions, but 80% of the time up there it's either really wet or really dry and dusty.
Here are a few tips for your first trip to MCBP:
- start slow and go easy for a few runs
- stay loose
- have fun
- know when to call it a day