There's a fair amount you can do. It's wonderful to have a super curious and outgoing snake in your life, but it can be challenging too. Also remember that freedom, in and of itself, is a primary reinforcer. As a result, some of my snakes who actively indicate that they want out are actually quite content to just sit with their heads resting at the edge of the enclosure once I open the door. They just seem to want to know that they have the option to come out.
For snakes that want more activities, here are a few things I do with my more outgoing guys: Offer regular enrichment inside the enclosure. Don't completely change/disrupt the whole enclosure, but add something new/temporary every week. It can be simple: a cardboard box, fresh cuttings from the yard, a plushy dog toy (they won't 'play' with those of course, but they do enjoy exploring and sitting on soft materials), a small shelf, a folded up towel they can crawl on/under...you get the picture. There are lots of possibilities.
Get one of those puppy 'playpens' with the fabric sides and the zippered top. I have a couple of these and when I don't have time to closely supervise a snake's 'outside' time I can put them in a playpen that I filled with enrichment items, zip the top, and let them trundle around in there for a couple of hours.
Consider target training. It's an excellent enrichment activity as it doesn't force handling on the snake but it engages their mind. And it has real usefulness for the keeper in terms of signaling that it is feeding time; it opens the door to teaching a snake to voluntarily shift between a permanent enclosure and a scale or a temporary enclosure during cleaning, or can signal the opportunity for non-food rewards like time outside of the enclosure. It's also handy as heck if the snake slips into a spot where you don't want them to be - you can target them out.