Players should block off / remove the pathways that lead into Fort Anachronism, as guests are getting lost there ; then build a bunch of food, drink stalls, information kiosks and toilets throughout the park because the people are hungry. As for research priorities here, the best options would be thrill rides, as only a few of them are available.
Rather than landscaping the fort, it can be used for a tracked ride. Adding tunnels, building near the existing scenery and the moat will boost the ride's excitement rating a lot.
The pathway near the dueling coasters is actually quite long, so players should consider building some rides or stalls around that area to prevent guests from getting bored.