GARRY Walker is limbering up for a mini-marathon. Beginning on Friday, and over the following fortnight, the 27-year-old conductor has eight concerts to direct with the RSNO in the orchestra's ScottishPower Proms series: three within two days in Dundee, then five in Glasgow.

He's already got five Proms concerts under his belt, having been with the orchestra in their short series in Aberdeen and Edinburgh. For some musicians it would be a grind - clocking up interminable rounds of schools concerts, public concerts for kids, and evening concerts of light classical music. For the personable and articulate Edinburgh-born conductor, nothing, clearly, is a treadmill; all of it

adds to the increasing experience and broadening horizons that are very much in his mind.

''These programmes of potboilers have their own difficulties,'' says the RSNO's young associate conductor. ''The challenge is to be original without trying to reinvent the wheel.'' He is quite candid about the music, admitting that, while it is grist to the mill for the large audiences attracted to popular - and light - classical music, he hasn't done a lot of it himself and finds it easier, psychologically, to come to grips with more overtly complex and dramatic music.

''With some of these really classic pieces, which have been heard so often - like the Light Cavalry Overture - I have some difficulty in finding them enormously exciting.'' None the less, he doesn't dispute the connection they make with audiences. ''We had a fantastic audience in Aberdeen for the Classical Gala; an absolute sell-out.''

His Proms programmes have him ranging from John Williams's Jurassic Park to Aaron Copland's Hoe Down, from The Ride of the Valkyries to Nessun Dorma. Also, in another new notch on his baton, he'll make his debut at the Last Night of the Proms, which will feature tenor Jamie MacDougall as presenter and Julian Lloyd Webber in cello classics. No shortage of breadth, then, for Walker.

Approaching the third year of his carefully graduated RSNO post, he's maintaining that breadth, building in as much versatility as possible into his technical and musical repertoire. He'll be conducting a number of education projects, a St Andrew's night concert with Phil Cunningham and Aly Bain, and a traditional Hogmanay concert. The meat of his third year, however, is unquestionably his first appearance in the RSNO's main winter season series of evening concerts, where he will tackle Mahler's epic Fifth Symphony.

The symphony, a gigantic and iconic piece - whose heartbreaking slow movement achieved universal familiarity through its use in Visconti's film Death in Venice - has enormous problems of technique, balance, and scale. Walker, who blooded himself in Mahler earlier this year with the National Youth Orchestra of Scotland in performances of the First Symphony, has known the Fifth all his life, though he has never conducted it.

He's already locked intellectually into some of the problems of the piece - ''the third movement is a huge challenge: you have to make it swing, and that movement lasts 20 minutes by itself'' - and, cannily, he has built himself a structured approach to the symphony. In October, he'll head down to Manchester, where he studied, to conduct a performance of it with the Stockport Symphony Orchestra, ''a very good amateur orchestra that I know from my time down there''.

As well as giving him the invaluable practical experience of getting his hands on the music early - there's only so much that can be achieved by a conductor sitting with a score in a quiet room - it will serve as a very useful dry run, to illuminate problems and challenges before he tackles it in Scotland, where he will give three performances of it early next year with the RSNO in Dundee, Edinburgh, and Glasgow.

Beyond his RSNO contract, Walker's career continues to develop successfully. He's working with all of the other Scottish orchestras next season - New Generation Artists' concerts with the BBC SSO and Masterworks concerts with the SCO. He has breathed new life into the revitalised Paragon Ensemble in his recently-completed first season as the

group's music director. He has three concerts in the Edinburgh Festival this August: two in the new late-night Usher Hall series, and - to the festival's biggest audience of more than 250,000 - he'll also conduct the SCO in the annual fireworks concert in Princes Street Gardens.

Beyond Scotland, things continue to develop for Walker who, next season, will conduct the City of Birmingham Symphony Orchestra in American music, the Philharmonia in contemporary music, and four concerts with the Royal Philharmonic Orchestra - which gave him his professional big break a few years back and with whom he is consolidating his relationship. Abroad, he has an immense gig next February when he will make his debut in the fabled Philharmonie in Berlin, conducting the Deutsche Symphonie Orchestra in an imaginative programme of Prokofiev and Brahms.

He refuses to be overwhelmed at some of the possibilities coming his way. He has turned down some prestigious gigs, including one from, arguably, the foremost UK orchestra (which he won't name, but was probably the London Symphony Orchestra). ''The time wasn't right. Some young conductors get in way over their heads. There's no point in burning yourself out. Increasingly, I control the flow of offers: I need time to study and learn - and to think. My problem is that I demand high standards of myself, so I'd rather just build gradually and have time to develop.''

RSNO ScottishPower Proms: Caird Hall, Dundee (Friday and Saturday), box office 01382 434940; Glasgow Royal Concert Hall (June 19-29), 0141 353 8000.