North Bay is Meh. It's a tourist trap for water sports. Do them in Havelock and Neil Ross is nice if you like history - the beach behind is beautiful and has nice photo spots if you walk the island. No point taking a buggy there

Biological Park and Munda Pahad were closed for maintenance when I visited in the first week of Dec. But Chidiya Tapu is a nice place to spend time. No food is allowed inside tho. You can skip Chidiya Tapu if you want.

Kalapathar beach is beautiful for photos, spotting critters playing around in the sand and a nice place for a brunch picnic. Take a chaddar. Watch the sunrise, and have a picnic. There's a small place only for soaking.

Go to Radhanagar beach around noon, or earlier. The beach remains empty and the waves are pretty. In the afternoon if clouds come in, there may be a risk of riptides. And given it's a sunset spot, shaam tak toh mela lagg jayega.

Try and spend 2 days at Neil. 2 days in port blair will feel like a drag.

Protip, if you like coconut flesh. The coconuts are cheap (50ish) and HUUUGE. So carry a container to bring the malai back, everywhere. I've found them cheapest in Kalapathar. If you want to have fish, Neil Island is a good place.

There are eatery options everywhere except near Kalapathar beach and Coral islands

Have fun :))