Inverness Caledonian Thistle are a club still young enough for men to have been on its staff for the entire span of its history.

The 1994-95 edition of the Scottish Football League Review – the precious and sadly discontinued annual collection of information and statistics – lists Charlie Christie and Graeme Bennett among the squad of players assembled for Inverness's first assault on the Scottish leagues. Today they are still serving the club: Christie as the head of youth development, Bennett as director of football.

The club were in with some of the oldest names in Scottish football in that first season: Albion Rovers, Alloa Athletic, Arbroath, Cowdenbeath, East Stirlingshire, Forfar Athletic, Montrose, Queen's Park and near neighbours Ross County. They finished a respectable but unremarkable sixth. Sunday could provide further confirmation of how far they have outgrown all those other clubs, County excepted. Inverness will travel to Dingwall for what could be the most rewarding Highland derby ever played. If they win they will be in the Europa League qualifiers. In fact, they could be denied it only if they drop points and St Johnstone beat Motherwell.

Being a football man in Inverness, like Christie, has amounted to having boundaries constantly extended over the past 20 years. First Scottish League football seemed unthinkable, then multiple promotions, the victories over Celtic and Rangers, then – this season – a finish in the top six. All that's left is for Inverness to reach a major final, to win one, and for them to play in Europe. The latter is in their hands. All those jokes visiting clubs, fans and journalists used to crack about "getting the passports out" for a trip to the Highlands might soon work in reverse.

"European football, if we were to make it, would be another climb in what has been an incredible ascent," said Christie. "The thing I like is that the fans who are with us are getting a reward. It would be something new for them and we do have a hard-core support. It would be lovely for them to be on the internet looking for flights to Estonia or Latvia, it would be a great experience if it happens."

Christie is untroubled by the cynical view that these days every Scottish Premier League club bar Celtic spends several months trying to get into European football and 180 minutes getting out of it. "Scotland's co-efficient is dire, although Celtic's run helped," he said. "Rangers won't be in Europe and our national team isn't doing well. I'm really disappointed with that, but it's not for a club like Caley Thistle to fly the flag in that respect. I think if we were to make it we would be there to enjoy the experience. Obviously we'd want to go as far as possible and certainly progressing through the first couple of qualifying rounds could be achievable."

Inverness has been described as the fastest-growing city in western Europe, its population of 57,000 expected to almost double in the next 25 years. The club has grown too, being promoted to the second division in 1997, the first in 1999, and the top flight in 2004. There was a relegation in 2009 but promotion again the next year. This term, their third consecutive season in the top flight, will deliver a finish of either third or fourth, their highest ever.

Sergei Baltacha, Steve Paterson, John Robertson, Craig Brewster (twice) and Christie have come and gone as their managers, all building the club now controlled by Terry Butcher. Christie's only regret is that there has been such little growth in their attendances. "The crowds haven't grown as much as we'd have hoped given the progress of the team," he said. "When you think we used to sell out 5500-6000 against Ross County in the third division and we're still getting those crowds in the Premier League."

The old Inverness Caledonian played to crowds of around 300 and Inverness Thistle to around 150 before the acrimonious, bitter merger between those old clubs formed the new entity that gained admission to the league. Suddenly they were playing to an average of 1500. A whole new constituency of fans responded to Scottish League games having shown little interest in the Highland League.

"We were only getting 500 people watching football in Inverness at the time before the merger. But when I played against St Johnstone for Caley in the Scottish Cup in 1992 we sold out Telford Street, 6500 people, although that was down to the rarity of not seeing bigger teams up here. We also took 5000 to Perth for a cup tie on a cold Tuesday night.

"But that's a frustration for the likes of myself who's been at the club since day one. I'd have liked to have thought we'd have a regular support 4000-5000 by now, whereas it's probably sitting around 2500. The club deserves more. I think that's why European football could be so important. It would generate even more interest in the club."

It's the expense of football and the exposed, cold location of Tulloch Caledonian Stadium which seems to dissuade many potential supporters from responding to their local club. Once upon a time another factor would have been resistance to the merger from "rebels" loyal to one of the two parent clubs. Christie still sees some of them, but it's a dwindling band. "I pass some in the street. Some say hi, some don't speak. But very few now. Things could have been done so much better at the time of the merger but the bottom line is that nobody, especially now, could argue that it wasn't the right thing to do.

"Neither of the clubs could have done what the merged clubs has done. Caley were in a stronger position at the time and might have progressed to the upper echelons of the second division. Going beyond that would have been very difficult. It needed the whole town behind us and we got the vast majority."

A win on Sunday will shape where the journey goes next.