First east coast RoadTrip

[KimBi]

We are a familiy of four arriving in Boston on July 1st and we are planning to spend the time there until the 5th.

Day 1 (5th): Leaving Boston, direction Niagara, we plan to have our first stop over at Ithaca.
Day 2 (6th): Continue to Niagara and the Canadian side too.
Day 3 (7th): ?
Day 4 (8th): ?
Day 5 (9th): ?
Day 6 (10th): Arriving in Washington DC

Wondering if we should have a stop i Toronto before we continue further south.
Our plan is to end i Washington DC on July 10th.

We would like to visit the following locations on the way:
Harley Davidson Factory
Amish county
Gettysburg

Any advice on good stop overs?
We are not the hicking type.
We do not need 5* hotels :-)

Our rental car can be brought to Canada.