I first went to Gili Trawangan in the summer of 2k14. After a short fligh to Lombok, friends and locals recommended we take a day to visit the Gili Islands. Tour packages varied and we opted to only visit Gili Trawangan, the most developed of the islands.
When getting from Lombok to the Gili Islands: Lombok hotel taxis will only drive you a block away from the port where boats leave to Gilis (both the public boat and charter speedbot port, we picked the latter; quicker and more convinient). Horse carts - the famous Lombok Ferraris - have a monopoly on the last block to the shore. Often tourists stay overnight at the Gilis and come with large suitcases so they offer the service of taking you down the stretch. The Ferraris charge Rp 50,000 ($4).It is essentially unecessary if you have no luggage, but it helps locals and could be fun!
Once by shore, be careful. Locals recognize tourists and will try to price discriminate your boat ticket using your naiveness. Don't even walk into their office - they'll offer ticket prices 3x more than normal. Walk straight past them to the boardwalk and government-operated, very run down, ticket offices. Shouldn't cost you more than Rp 350,000 for a round trip.
In Gili Trawangan: it is the perfect backpackers destination. The 3km in length and 2km in width island has a dirt road (see above) that goes all the way around it. You rent bicycles (no motorvehicles allowed, only Ferraris or bicycles) by the hour and explore. All around the coasts are small coffee shops, restaurants, bars and guest houses. Very simplistic, tropical and purposely undeveloped. Further "in land" you'll find more exotic resorts for those looking to stay overnight.
Note: Gili Trawangan is also known for its drug tourism; since 1980s it's been a location where drugs are freely available. Some are openly advertised on the roads. Be careful!
If you're around Asia and looking to travel somewhere off-grid but not risk your life, Gili Trawangan is great. However, since it's only approachable by water from Bali or Lombok and there isn't much to do besides enjoy nature, it's usually considered as a side, one-day destination.
On the drive there, the driver stopped for some incredible views...
The Ferrari we took to the shore. Bumpiest, most uncomfortable and unecessary 9 minute horse cart ride I've ever had. Must have been less than 300m.
But as always, travel is worth it. Already half way across the world in Indonesia, took a short morning flight to Lombok, a taxi, a horse and a speedboat ride.. YOLO right? The reward of seeing this pays off: