We recommend you stay in Novo Mesto to grab some supplies for your trip. Novo Mesto is well equipped with multiple supermarkets and stores.
LIDL (Our favourite) - Ljubljanska cesta 27, 8000 Novo mesto, Slovenia
Qlandia Novo Mesto. (This has everything from Linen, Sportswear, Camping Equipment, Supermarket and more) Otoška cesta 5, 8000 Novo mesto, Slovenia