Moved to Destinations.
If you are looking for advice on visa and rental property search, there are companies which specialize in that. They deal with visa applications/renewals and lawyers to deal with contracts plus translation. Buying property is a whole other ball game and I suggest you read the superfine print before you embark that route. A few different visas you can choose from to enter the country. Depends on what you are looking to do.
For shore diving in Bali, I do that quite often when I'm there. You can buy a few tanks from the local dive supply shop and fill at spots along the big diving places like Tulamben/Pemuteran. You can do even EAN if you know the operator well. Renting tanks are a little bit more problematic unless the dive shop knows you very well. I go around looking for new sites often, most of the time they disappoint but once in a while you find something good.
Getting a guide is pretty easy if you dive with the local resort/shop. There are a few local freelance guides who speak decent english and can spot. Of course you can also just go to the dive resort for a day fee and dive from there.
Getting around is by car. You can lease a decent car for about Rp3.5million (newish car) a month that can lug your gear. A driver you can hire for about Rp200k a day. Many of my expat buddies drive around themselves for the major stuff but the little roads (and there are plenty) are tough at first. Balinese traffic is...errr different to the rest of Indonesia. Motor scooter drivers don't look before the dash out into the main road, change lanes on a whim and driving within 2cm of the next car are the norm. Takes some getting use to.