By Air: There is a connecting flight from Delhi to Pantnagar.
By Train: There are three trains from Delhi to Nearest Railway station (Kathgodam)
By Road: It takes about 7 hours (including a lunch break) and there is plan to use a Bus/taxi from Delhi to Nainital.
Visa: In case you need invitation letter for the visa, please write to Manish Naja (manish@aries.res.in).
More details on this will be available very soon. Details on e-VISA can be obtained here.