How much rad resist is needed for The Glowing Sea?

I've just entered The Glowing Sea for the mission in the main quest line, but am having some difficulties.

I went in wearing a Hazmat suit (giving 1000 rad resist) in order to minimize radiation damage, and am receiving <1 rads.

However because I cannot wear armor with the Hazmat suit I am struggling with enemy encounters. If they manage to attack me they do an excessive amount of damage.

I have a suit of power armor that currently offers over 1000 rad resist, so I could wear this, however I don't really want to burn through my fusion cores whilst exploring.

My question is: How much rad resist is needed to minimize the radiation damage in The Glowing Sea?

Would 100 rad resist from taking Rad-X allow enough protection to receive <1 rads, meaning I could wear my normal armor?

Does the background radiation increase the further southwest traveled, meaning I would need more than 500/1000 to receive <1 rads in the furthest reaches?

Solution 1:

Spoilers ahead

If you finished the quest The Secret of Cabot House, you acquired a couple doses of Mysterious Serum.

Instead of increasing your rad resistance, that serum removes 10 rads per seconds during 3600 seconds (an hour). Since most areas in the Glowing Sea inflicts about 10 rads per second, you can cruise around without any effects. A single dose will last long enough for you to do the quest and explore the area.

Solution 2:

I popped like 2 rad-x and was fine. I think I used about 3 rad away while navigating, but it wasn't anywhere as near as bad as the NPC's lead me to believe.

However, there are some areas you won't want to go walking about in, as they have far higher rad ratings.