I wouldn't take the ferry wth luggage.
I would park in a New Jersey Transit lot and take the train in.
You are lucky, parking on a sunday should be a breeze, probably no lot will be anywhere near full.
Take the train to Penn Station, then a cab to the doubletree. Great hotel, you'll like it.
From their website (www.njtransit.com):
I am visiting/driving to New Jersey and I want to take a train into New York City. Where can I find daily/overnight parking lots adjacent to your stations? Back to Top
If you are traveling from Southern New Jersey, you may consider parking at Trenton Train Station where you can catch a Northeast Corridor train to New York Penn Station located in midtown Manhattan at 33rd Street and 7th Avenue. For related parking information at Trenton Train Station, please call (609)599-9614.
If you are in Central New Jersey, you may consider taking the New Jersey Turnpike to Exit 11 and taking the Garden State Parkway North for two miles to Exit 131A to Metropark Train Station where you can catch a Northeast Corridor train to New York Penn Station. For related parking information at Metropark Train Station, please call (732) 906-1661.
If you are coming from the Northwestern portion of New Jersey via Route 80, you may want to consider parking at the Dover Rail Station and taking a MidTOWN Direct train to New York Penn Station. For related parking information at Dover Train Station, please call (973) 366-2200.
For parking information at any other NJ TRANSIT rail station, please call the Transit Information Center. Agents are available to assist you daily between the hours of 6:00 a.m. and midnight at 1-800-626-RIDE in the NY, NJ, and PA vicinity, or at 1-800-772-2222 within New Jersey. South Jersey callers may dial 1-800-582-5946. All other areas should dial 1-(973) 762-5100.