The Kirkintilloch side head East with one trophy already in the cabinet and a potential four more to follow.
As well as being through to the last eight of the Scottish Junior Cup, they are currently top of the West Super League, have already won the Sectional League Cup and are still in contention for the West of Scotland Cup and Central League Cup.
Maxwell knows that last season’s East Region champions will provide a tough test for his side - but he believes his squad are up for the challenge.
He said: “I would say it’s the biggest game of the season, it’s a turning point in the season.
“There will be a point in a season where defining factors kick in, whether you’re going to go on and do something or whether you’re going to lose and go back into the pack.
“I think the supporters, the committee, the people of Kirkintilloch see this as a massive game. If we win it I can only see it galvanising us for the business end of the season.”
“We’ve put out two good East Region sides in Musselburgh - obviously we played them on a neutral venue so there was no advantage there - and we went through to Penicuik and scored four goals and they are sitting in the top four in that league.
“Bonnyrigg are a very good side and have been very consistent this year, they pass the ball really well. But as long as we don’t get rattled, we stick to our game plane, keep our discipline then I think Rob Roy can hurt any junior team in the country with the ability we’ve got in the squad.
“But again you’ve just got to grasp it, grasp the opportunity, grasp the occasion and perform the way we can.
“Regardless of what happens they’ve won a trophy and nobody can take that away from them.
“But the Scottish Cup is something different. It’s probably the only affiliation in the world where people can say winning the Junior Cup’s bigger than winning your league, there’s an argument for that.
“People get caught up in the Junior Cup. I was lucky enough to play in a Junior Cup final myself [for Bathgate in 2006] and to experience that full day is something which will stick with you as a player and I try to pass that knowledge of the occasion on to my players.”
Maxwell also hopes that Rob Roy’s success - achieved against a backdrop of having no permanent home and having to play home games at Cumbernauld - can encourage more members of the local community to turn out and support them.
He said: “We have got a good support but I think the support will get bigger.
“Scottish football’s not really attracting in the top league just now. Celtic have won the league and Rangers are struggling and that’s the two main supported teams in Kirkintilloch; come and support your local team, come and drive your local team on. They could be on the verge of something great.
“They’ve had a good season but a good season could turn into a great season, come and give them that support, that belief. It’s your local team, come and support your local team.
“It’s a great story - no park, small budget, 100/1 shots to win the league.
“There’s something brewing and if the players believe in it they can achieve something.
“If we miss out and fall short, overall I’ll be immensely proud of what the players have done this year because they’ve taken the season into March, no matter what, probably into April.
“If we win on Saturday we go into a two-legged semi-final in April so I think Saturday’s a pivotal, pivotal moment in where we could end up.”