My reading of the state park map is that the park is on the ocean side of route 1, so that’ll eliminate going up any real hills. I’m not really familiar with that section of the coast, though.

It also sounds like you want an excuse to expand your antenna collection. Go for it! Antenna experimenting is fun. Set up two, and try some A/B testing, or use WSPR or RBN.

Its an interesting problem you’ve found. As a frequent SOTA op, its not one I encounter :D

To get NVIS just use your regular 40m antenna, but set it up closer to the ground. Depending on your mast height, it might be NVIS already.

What park is it? Maybe there’s a spot off the beach you could operate from?

A j-pole is a half-wavelength vertical with a quarter-wavelength matching section on the bottom.

It turns out that the 70cm band is about 3x the frequency of the 2m band (150MHz * 3 = 450MHz, close enough to each band). So the 2m the long leg of the j-pole is 3/4 wavelength (1/2 + 1/4 matching section), and on 70cm the long leg is 2.25 wavelength (3/2 + 3/4 matching). Both are an odd number of quarter waves, as we expect. The ham who made that briefing probably discovered in their testing that the matching stub wasn’t good for both bands, so they added a second one for 70cm.

This is not a novel design, Arrow Antennas has been selling one like it for years (https://www.arrowantennas.com/osj/j-pole.html)

This has been my experience using multiple HTs on the same band.

This is the reason to support ARRL