this can be easly implemented with a perk(like the slaver perk)
perk: camper
req: make a tent
descr: you had made your first tent, a huge realization in the wasteland, congrads!!!
ef: you gain 1000 xp
ranks: 1
so if you make a new tent you wil not gain this perk again
also, when creating a tent add a condition
if(perk_variable==0)
{
gain perk;
perk_variable=1;
}