The men's club was thrown out of the university sports association in 2009 after a series of alcohol-related incidents and faced a long, hard battle to be reinstated.
Last year, the first XV won the British Universities and Colleges Sport Scottish League 2A, opening the way for them to re-enter the top tier of Scottish university rugby, in which they were third this season.
Now, Forrester believes the team deserves to compete in the national league set-up. "It's a realistic goal and we have the numbers to do it," he said. "I want three teams playing each week. We just have to work out the best approach and juggle the various logistical problems."
Forrester's current post was created by the university's sports association, in partnership with the Scottish Rugby Union, as part of an attempt to add credibility to the beleaguered club, which is more than 140 years old. The post was previously occupied by Peter Jericevich, the Ayr scrum-half who is rejoining GHA, and before that by former Ayr stalwart Stewart Magorian.
Forrester is in charge of a men's squad with 93 players and three teams, a women's squad, and an intramural competition.
"Calum worked as our forwards' coach last year and having him take over from his Ayr team-mate has been a seamless transition," said club captain Richard Murdoch. "Having already worked with us last year, he knew where we were aiming to take the club in terms of its development, and his experience as a former Glasgow player has been invaluable on the coaching side."
A Scotland internationalist at under-19, under-21 and sevens, Forrester has the pedigree that a club seeking to regain its status as a powerhouse require,and he feels the players are more than buying in.
"It's a completely different bunch of boys - it's a really good environment which has been created over the last few years," he said. "Anything that went on in the past is long gone, it's not relevant to this group."
In a week where many have questioned rugby development in Scotland, Forrester believes his squad have a number of prospects for the future.
"There is a huge amount of talent in this squad and I hope we can get into a position where these players can contend for Scotland age-grade selection.
"A number of the boys have the ability to play at a higher level and our new partnership with Glasgow Hawks is a good progression for some of them if they remain in Glasgow."
Coaching has provided Forrester with a release, his playing career having been beset with injury problems, including a full knee reconstruction. He went under the knife again last week for an operation on ligament damage, which will keep him sidelined for the rest of the season.
"It [coaching] is something that I enjoy and something that I have always planned to do," he said. "But in terms of [the contrast with] playing, it's very frustrating; if something's going wrong on the pitch I have to realise I am not able to get on and do something about it.
"I hope I can return to Ayr next season, but I have to see how my knee pans out. I have to think about the rest of my body - it's just about whether I make a full recovery. Rugby has given me a lot all my life and I plan to stay involved, whether it's with coaching or playing."