Accommodations, huts and camping
There are many ways to find accommodation in the towns and tourist destinations on the coast: major online booking services and local websites. I am not going to cover them here.
There is a network of mountain huts. Those at Platak are open all year round and provide beds, food and bars. Others are open at weekends except in winter. They will have a room accessible in winter with bunks and a wood stove. Smaller huts are unmanned and basic.
There are plenty of campsites on the coast. Most are large with entertainments and pools, and a price tag to match. There are smaller, cheaper campsite if that is more your thing, most are listed here.
Wild camping is illegal in Croatia. Outside of the national parks you are unlikely to have any problems, however there are plenty of huts so there is rarely much need to carry a tent.
Similarly camping on the beaches is also illegal, but given the numerous isolated and beautiful beaches it is very, very tempting - but please be discreet.
Mobile phones work virtually everywhere in Croatia. Close to the Slovenian border your phone might choose a Slovenian network but with the abolition of roaming charges within the EU this isn't a problem for most visitors.
If you want to buy a local SIM card then my recommendation is Tomato SIM cards can be bought from any VIP phone shops. Monthly package without a contract can be bought at remarkably low prices. Be aware that the Croatian government apply an extra 10% tax on phone credit, so 20 kuna credit will cost 22 kuna.
The mountain rescue service (GSS) and Coastguard can be reached on the usual EU number: 112