Gulmarg being one of the most important getaways around Srinagar, you need an entire day to spend in the town. It would be better if you can start early and reach here by 11am to end your day before it gets dark.
You can take a cab from Srinagar bus stand. Also, you can get transfer through Srinagar local transport but it would drop you halfway. From their, you have to arrange for your personal transport. Once you are at the base point, you need to rent another car which has chained tyres as during rainy season, the usual cars get slipped.
Gulmarg do not have railway station of its own. The nearest railway station is of Jammu which have air connectivity to Srinagar. Jammu has rail connectivity from all parts of India and all major junctions.
Srinagar airport is nearest to Gulmarg. You can take direct or connecting flight from all four major metropolitan. Almost all major carriers ply on this route and offer cheap packages to Kashmir which includes all major getaways such as Gulmarg, Sonamarg and Pahalgam, including local sightseeing at Srinagar.