Road way and Elevation issues while traveling

In general, if you go on US labeled roads/routes you'll be good. I.E. US301, US1 etc.

For grades I like Google Earth (not Google Maps).

Once you get your route input, right click on the line and you can show the elevation along the route including grades.

As long as you aren't underpowered and semis are traveling the road, you should be able to manage it fine.

Lots of low clearances in the towns and cities of the NE. Other than that not to worry.

We plan our route to avoid tolls. Some are unavoidable. Our GPS does a fair job avoiding tolls.

If a big rig uses the road, you can too.

Another question is do you want to avoid tolls. In the NE, many of the highways and bridges have tolls. Pulling a toad means some of the tolls are rediculous.

We are going to Maine in August from Maryland. We've driven I95 through NYC and up to Boston in cars so don't need to see that again.

In our RV pulling a toad, we'll go up I83 and other interstates to Birmingham. Then wander our way through Vermont and New Hampshire before getting to Maine. Should be a nice, scenic trip.

Old Biscuit is right. We also use a paper Atlas and read the signage.

The Mountain Directory (east and west) is an excellent way to check routes for mountain passes and grades.

Many east coast roads are narrow and do not have true shoulders, many drop off to grass.
GPS units are not always accurate. If concerned about elevation and roads look at a Trucker's Atlas. I would not jump out and buy one until look at one at a truck stop.
We have traveled much of the US using primary and secondary federal highways, primary and should not have state highways.
Pay attention to signage and think ahead! We watch for signage normally pertaining to truckers. Most of the time it keeps us out of trouble.

Biscuit gives good advise. My piece of advise is to not trust your GPS if you use one, us it as an advisory unit only. If going to a campground, follow their instructions on how to get there.

I thought the smaller roads in Maine were either trying to throw you in the gutter or into the other lane