RE: Marrying the girl in Modoc
Never had 6 members, well I might have done once. I had Gorthar leave me because he needed to run and help his people, so I got a full party of adventurers to the Enclave anyway. I was surprised to find him levelling up despite not being with me.
As to assaulting the base all guns blazing. I usually do it with 2 people. Me and Vic. Both with Power Armour, and him maxed out with a Guass Rifle, me with Sniper Perk, Better Criticals, 10 aps, Faster Rate of Fire Perk + a Bozar/Vindicator and Guass Rifle. And the LE Red Ryder BB gun for fun.
It gets less messy with 2 people and for some reason, Vic is the only other person who can sneak into the base without raising the alarm. I've done it several times and I know I'm not the only one. However, the Turrets and Robots usually shoot us. I don't think with decent armour and plenty of stim packs - you should have about 80+ and 15+ super ones at this stage that it's that difficult blasting through the complex. Especially once one level is cleared and you get Cassidy and the rest in on the action. Great fun though.