Oh, man. I got the Hardcore Gunners, Hardcore Raiders and More Patrols mods so when I go into Lexington, that Behemoth is the least of my worries. And none of them are happy to see me, except maybe the ghouls.
Tips: Wearing power armor + maximum upgrade sledgehammer + 3rd person view + normal attack. You will be an invincible even if you face a legandary behemoth.
Look in relevant locations to find ammo boxes. Places like military forts and bunkers, as well as law enforcement buildings will no doubt have security lockers filled with weapons and ammo. It's also worth clearing our Raider and Gunner bases to find their stashes as well... U can allways Buy any ammo by traders or build trade hub in one of your settelments to never get dry on ammo
I do my early game ammo shopping at Thicket Excavations. Do Sully's quest, then wait till level 12, the pit will be full of raiders. Kill the regular raiders and loot to the mid level, but leave Sully alive at the bottom. The junk and ammo crates will respawn in the time it takes to jog back and dump your loot at Sanctuary or Starlight(without fast travel). If Sully is dead he will be replaced by an unnamed high level raider after staying away (20 game days?). As long as the leader stays alive (zone not cleared) the loot respawns. If unnamed, then the raiders also respawn. The Scrounger perk increases likelihood of 5.56 above level 26. I run a loop through the Excavations and Bedford Station, which also rapid respawns the junk and steamer trunk. The steamer trunk by the water tower above Red Rocket and the safe in the house down the street also rapid respawn if you don't clear the mole rat den. Coast Guard Pier is another rapid respawn even when cleared, that has guaranteed .308, 10mm, and shotgun ammo. There is also an unmarked trader in a trailer north of Fairline Estates that has large quantities of ammo, including 5.56.
