Yes, since I've been sleeping outdoors the whole time recently, it was nice to finally relax for a change. Thank you.
Literal
Yes, this-lately outdoor-sleeping only [copula-だったものだから], after-a-long-time-[に] slowly could-do [polite-ました]. Thank-you.
野宿 'sleeping outdoors / camping rough' (野 'field' + 宿 'lodging'). ばかり 'nothing but / only' emphasizes the repetitiveness. ものだから is a causal expression — 'seeing as / because (of the circumstance that)' — more explanatory than から alone. 久しぶりに 'for the first time in a while' sets up the relief.