Welcome to SB! Missing in this is the basic: where will you be traveling from, how long do you have, time of year etc. Flight durations, datelines and connections have a way of eating into vacation dates, not to mention the sort of delays you can encounter on the ground. Flying out of SFO I can land at Denpasar (DPS), Bali and be in Tulamben by dinner time, 2+ days after leaving home. A good night's sleep (because I'm back on Bali!!!) and I'm ready to dive the next morning. That's about as fast as I can do it and it's now almost 4 days after leaving home from on the west coast.
Surface travel on Bali is part of the island's charm, which is to say don't even think of driving yourself. Stay at a place like Liberty Dive Resort in Tulamben and Wayan will arrange to have a driver at the airport, holding a sign with your name on it. It's a couple hours drive through beautiful scenery but not something I would want to do at night necessarily. An afternoon arrival time will avoid that. Most resorts will provide this sort of pickup service, arrange tours, drivers etc. just ask.
Maybe add Ubud to your list for topside attractions when you are done diving. Worth an extra day or 2. Yeah, do the craft markets but it's the out lying areas (like Keliki district) that are the real attraction. There are lot's of folks and outfits that can setup some land based touring, find a good one and they will no doubt help you have a more trouble free time. The diving in Tulamben, Serya and nearby Amed is quite superb. Chances are you'll be planning your next Indonesian dive trip before you leave the island! // ww