Any idea of special points layout and perks
Guessing these will be good areas
Big leagues
Demo expert
Locksmith
Lifegiver
Luck tree?
I think you're better off just melee. Explosives are situational, and even unupgraded, will rock when you stumble on 5 + enemy cluster. There's only 3 really good melee builds ; a slow and strong one in power armor where you use your action points only to tackle enemies down with the 10 str perk, a sneaky one where you use blitz ( 9 agility ) to sneak attack enemies using vats, and a fist - luck oriented with gun fu ( 10 agi ), tons of luck and the fist perk at 5 where every critical hit paralyze your opponent.
If you wanna go explosive, I suggest you get big guns with it. Rocket launchers and fat man's damage is boosted by both big guns and explosives, making them devastating. I also suggest sneaking around because it's very important to get the jump on others while using explosives. Small areas can be dealt with with a flamer or various mini guns. Just include in your build a way to make caps, like 7 charisma and settlement vendors. Heck, place 5 weapon vendors side by side so you don't need to rest often for your ammo.
But mines aren't good with melee characters. They're good with sniper and sneaky types, so only the grenades are left. I admit cryo grenades with melee is nice though.