The north Wales outfit stormed their way to last year's SWALEC League One East title, winning 19 of their 22 league games and running in 119 tries in the process.
All of the above was achieved with a young side, many of whom were experiencing their first taste of senior rugby.
Now, with his squad a year older and on the back putting some silverware in the Parc Eirias trophy cabinet, former Wales prop Horsman believes his side are ready to step up another level.
"It has been a good start to pre-season," he said.
"It sounds stupid but the players are a year older and wiser now. They've got a full campaign under their belt - not just winning the league, but doing it by playing some good rugby.
"The Championship is going to be a challenge, we know that and we're going to come across better sides with more quality.
"But if we play to our potential, which I know we can, we will cause some damage to the opposition."
The north Wales outfit will come across two of their main Championship rivals in Ebbw Vale and Bargoed at next month's Foster's National Sevens competition.
And while accepting his team will come up against some high-quality sides, Horsman says he isn't expecting a drastic shift in how the opposition will play.
"I don't think the style of play will be too different - it's more about what the individuals from each side can produce," he added.
"We've got a similar squad to last year and like any team, we want to add to the group. But it's about doing that at the same time as producing local talent.
"For us, it's about developing all the teams in north Wales, right the way from junior and college rugby through to the age grade teams and into the senior side."
Horsman has added two centres to his squad for the coming season, Huw Grundy and Tom Hughes both joining the Eirias set-up.
He added: "The new players aside, the biggest thing for me is we've managed to keep hold of our players from the Academy.
"Previously, they might have left the area to go to University but they've stayed here and that's massive for us."
While regularly running in four or more tries per game last season, RGC were certainly entertaining on the eye.
But with the new season fast approaching, Horsman is adamant his side can adapt their game if necessary.
"It's a misconception that we throw the ball around a lot," he argued.
"We play to what the conditions and opposition allow us to do. We scored 10 tries from driving line-outs last season - that shows we can play a tight game if we need to.
"What's important is that we don't play to a rigid structure, we have to be flexible and adapt our game to what's needed."