If you cant get long term parking at Pula, you could clear customs there and fly a few minutes north to Vrsar Airport – LDPV.
LDPV used to have customs and immigration check during summer but they removed it because of low demand. However, it’s still available on PPR according to AIP.
Arriving from Schengen area you need only immigration and it’s important to underline that in PPR to avoid unnecessary customs cost.
For the trip back, Calvi and Bastia take the BP card and make convenient stops for fuel. Far cheaper than italy AFAICT.
If you don’t want to make a stop juste before a water crossing, Cannes LFMD has BP too.
