Jeff Hughes completed the rout after the break to end a barren run of form on the road for Rovers, who claimed their first away win in 11 games.
"This is the level we expect for the rest of the season and we can win a lot of games and if we win them we can close the gap," said Trollope. "We are in really good nick and looking forward to the last 12 games but not getting too excited as it is a big gap to close.
"We came here with huge respect for (Swindon boss) Danny Wilson and his team and we knew we had to be good defending but when we had the chance we did play good football.
"It's been a long time away from home, I think Southampton was our last away win and we had stalled on the road but away performances have improved of late. We came with a lot of confidence and game plan which worked."