I am putting the finishing touches on our February trip to Ireland. I know the weather may be less than ideal but we are planning to head to Inishmore for the day. I have two questions. Since we will have a rental car is it possible to drive to and park at the ferry terminal in Rossaveel? I would hate to pay the additional fee for the transfers while our car sits at the hotel. My second question is are there services available on Ishmore in mid-February (i.e. dining, mini bus tours, or weather permitting bike rentals)? I appreciate all the advice these forums provide. Thank you.
Yep, you can drive to Ros A' Mhil and park your car at the ferry terminal. I'm doubtful that there'll be much going on on the island in mid-February, but the easiest way to get the best information is to ring the tourist office on Inis Mor.
Per Marcus, you can drive from Galway out to the ferry landing, and for your group of 5 (per your other post) it would no doubt save you some money.
Aside from the vagaries of the weather in Feb., be aware that the days are short too, ie sunrise around 8:15 and sunset around 5:00 PM, so your return drive back into Galway will be in the dark as well as (possibly) in the rain. Your call - but for the comfort, convenience, and safety involved the transfer fee might be worth it.
Dun Aengus is the big attraction, and the Bronze Age fort really is a sight to see. Know that there's no barrier between you and eternity at the side of the cliff, however, so a great deal of caution is advised.
A fun alternative to cycling (especially in Feb.) would be a pony and trap tour with this guy:
https://www.tripadvisor.com/Attraction_Review-g551521-d3397395-Reviews-Inis_Mor_Pony_and_Trap_Tours_with_John-Inishmore_Aran_Islands_County_Galway_Weste.html
Would at least keep you dry and comfortable if the weather turns sour, and exploring the island with your own private tour guide would help make the most of your day out with your family.