How was told at delivery that a public level 2 would ad about 18 km per hour of charge. Does it make sense to you guys ?
Scroll down to the chart. 17km/h is achievable with a wall-plug. PlughShare is generally pretty great by identifying how many kW are available at the charger. The highest you'll see is 11kW, because that's the most your car is capable of doing. If there are two or more destination chargers strung together you'll see that cut down by half or more if multiple cars are charging. Level 2 isn't all that predictable, but perfect for overnight charging.
Also, do check PlugShare's ratings because it's a good predictor of the reliability of the charger. The few times I picked a hotel with a poor rating (because I loved the hotel, or location or whatever), I was burned with a broken charger.
For a trip to the east coast, the math will work against you. On a TM3 your maximum charging is 71km/h but you'll be driving faster than that, so for every 1.5 hour of charging you'll be able to drive one hour. Unfortunately, until the Tesla charging network is built up east, this isn't going to be a fun trip unless you plan to do evening stops at hotels with Level 2 charging.
Also! You probably know this already, but we've had one person on the forum that didn't know this, that you can't use any chademo/css chargers along the way. They're almost as fast as superchargers, but they don't presently work with the TM3.
http://abetterrouteplanner is a terrific resource. It might recommend you go through the US where there are a few more superchargers to hit. Mostly, you'll be fine, just pick good hotels with reliable level 2 charging and call ahead to make sure they're active.