The combination of a car and your request is difficult.
Spirit:
As oldergent suggests, options are available.
If you are speaking about parking just for your purpose, there are many between the Javits (11th Ave) and MSG (8th Ave), going both uptown and downtown. If you are hopeful of parking overnight, most of the outdoor lots do not allow for, over-night parking, issues with liability insurance. Check into it! Parking garages do exist, but could become very expensive. Hopefully your auto is nothing special, you may be the benefactor of a souvenir or two, as a remembrance of your trip.
Parking on the roof sections of the Port Authority Bus Terminal may work well, affordable, safe and all-night access. A height restriction exists,…. just as many of the indoor garages, not sure, but I think it is 7 feet? I believe the elevated ramp entrance is at 9th Avenue, you will be headed uptown,(one way going north), at 40th street on your right/east side of the street. Short walk to Javits, 10 minutes.
Suggestion. If your schedule allows and in the event you are an early riser, parking can be had on the streets, in the neighborhood of Chelsea. Drive south, down 11th Avenue. The area is located between, 19th and 26th streets, do not go further east then 8th Avenue. Just take note of the One-Way signs, and READ the sign just above your head before you park. The walk back, again should be no more then 15/20 minutes. If you park anywhere on the street in NYC and get towed, your probably looking at $225.00 minimum and a major pain in the ass. READ the signs.
In the event you bag the car, The Red Roof Inn on 32nd Street (northside) just off 5th Avenue, I have found outstanding and reasonable, also has an exercise area. In the event you may indulge, it is SP friendly or as much as one can be in NYC. It is located in a very small Asian district. If you walk robustly, you can be at Javits in 15/20 minutes, cab ride will be $6. Should you consider flying in, my experience suggests landing in Newark as opposed to LaGuardia as I have always had better luck with the traffic headed into NYC, unless of course it’s an off hour arrival or departure.
Stay of out of Newark/Elizabeth and the airport area hotels. In my opinion, and on an affordable budget, it is just too much of a crap-shoot. In the event you do decide to stay in Newark, if needed, the NJ Transit Train service is great, but I believe the last train out of NYC and back to Newark is 1:30AM?, check first!
If you head out towards the Meadowlands/Secaucus, north and slightly west of Newark, many options exist, I would not necessarily suggest affordable but certainly decent. Parking is not an issue. Many hotels here offer shuttles, Secaucus/NYC train service is available but not convenient to the hotels, meaning you cannot walk. Also, check the train schedule, as it does not run all night.
Jersey City is also an option, parking should not be an issue at the hotels. I have stayed at the Ramada and the Courtyard Marriott, again not necessarily affordable but decent. Light-rail/PATH train, NJ transit bus ($2 one way?), runs out of the Port Authority on 8th Avenue between 40th and 42nd Street, and obviously cabs are options. I seem to remember, the PATH train running all night, but check! A cab ride from NYC to Jersey City will probably run you in the neighborhood of $30.00. If you do this, see if you can get the cabby to flat it, off the meter, $25/30, in the event traffic is an issue, you should make out better. Many gypsy cabs( ref. Jersey City/Hoboken) operate in this area,… just use your best judgment if you so chose.
Related tid-bits. Park&Ride bus lots are available in NJ around the Meadowlands area. These are designated as, supposed commuter lots. Again, overnight parking could be a problem.
If I think of anything else, I will offer…….
Safe trip, good luck…….