Or maybe start with 120 miles.
There are single Worrell legs that are that long.
I think that alternating between the north and south 500 might be an interesting idea. i.e. this year south beach to Tybee, next year, tybee to VA Beach.
What a lot of the people that have done the T5 but not the W1k don't realize is that it's a VERY different world as you keep going north.