One of the short-cuts used by some taxi/car service/local drivers familiar with gridlocks leaving JFK to mid-town is (instead of going out of JFK Expwy to VWE or I-678 North to the Grand Central Parkway/LIE is to to take the Woodheaven Blvd. all the way north (traffic lights, yes, but it's 3 lanes each direction at all times) toward Queens Blvd & then ease back onto the LIE West to the tolled Mid-town Tunnel - for the East Side/Grand Central Terminal, 34th Street/NYU Med. & the Upper East Side. It's not the fastest time-wise but I-678 North is bumper-to-bumper all day long due to long-term & ongoing restrictions with narrower lanes, travel time on that stretch alone is easily 15 to 30 minutes without accidents or poor weather.

It's best to avoid the Belt Parkway westbound in the PM hours, again, long-term & ongoing constructions along the route with narrower lanes, and POT-HOLES, huge ones especially after poor weather & cars slamming their brakes or dodging into other lanes, etc. to avoid denting their axles & rims or getting flat tires - which can be done in 20 to 40 minutes with all is good during regular PM rush hour along the shoreline, the next bottleneck for those who like the scenic VZ Bridge along the way is traffic often come to a near halt by the time you reached the Gowanus/BQE west in South Brooklyn, before going over the "top" to the split for the Battery Tunnel or continuing to the Brooklyn or Manhattan Bridge exit for Lower Manhattan - there is practically no chance these days to make this run in 45 to 60 minutes, from car rental lot to NYU - 90 minutes is about right but with bad weather, broken down motorist or road "incidents" 2 hours would be considered reasonable.

For the morning trip from Tribeca to EWR area, 45 to 60 mintues normally will suffice and yes, Holland Tunnel is the best bet but know how to go north for the Lincoln Tunnel (use the 10th Avenue entrance behind the Postal facilities for the best/fastest approach at any hours of the day/night coming up from the southern part.) Just be careful with some of the signs near the Tunnel during rush hours for things such as Bus only, No Left Turn 6-10 AM, etc. but traffic agents are always out at key intersections to direct for smoother traffic flow.

Lastly, ask the hotel about any parking specials or deals for guests, as it can be rather costly overnight & you won't outsmart local residents for finding a nearby on-street free parking spots.