There is plenty of books out there advising you on where to go and what to do. But sometimes the extra weight isn't worth the pull. Use the local knowledge and backpacker reccomendations to inspire you. Pick up a local map when possible and keep your options open. Carry a light reading book for the early nights and for beach time. There are plenty of opportunities to swap books in hostels en route, don't become bogged down with extra weight!!
When we booked our flight tickets to Bangkok, we hadn't a clue of what kind of trip we were going to take. On a bike ride in Belgium we questioned the idea of a bicycle touring trip. We purchased the Lonely Planets Southeast Asia on a Shoestring, looking for ideas of where to go and what to do. We only had 12 weeks travelling time and at first we were overly ambitious with the amount of countries we could visit. Narrowing our options to the four countries in the Mekong region, so we could have quality over quantities. Their travel guide, is a 976 page doorstop of a book, and carrying it with us was a big regret. It tries to cover such a vast section of the world; which is packed full of diverse cultures, resulting in a very brief description, only scratching the surface of many places.
Despite weight and size issues, Lonely Planets style of description, even when concentrating on one part of the world, still lacks a killer edge. They cater for the needs for too many kinds of traveller and so you will find only a small percentage is relevant to you. You won't use it the majority of the time; finding restaurants yourself is easy when you know what you like and using such hints as a restaurant packed of locals is a clear indicator of fresher food.
However, if you do like to learn more about the local culture and history, the RoughGuides presents a more in depth description. Plus they include several smaller maps in cities far more frequently than in the Lonely Planet, giving you the essential landmarks and transport stations.
On the other hand ,getting a pocket sized language guide can be very useful. It can be great fun playing charades, but when needing a solid answer at a critical time, this book will be priceless. It's also great to get to know a little bit more about a local not just by hand movements. Giving credit to the Lonely planet with their edition on this region of the world. Also having an Ebook.
Another great book which will work in every language in the world is, PointIt. You will overcome 99% of your requests by pointing at different pictures. Whether the problem is the size of the bed or the fact that you are vegetarian. This also comes as an app.
The picture is a snippet from the book; Cyclebabble, its quite a funny read with a some handy tips. I'd recommend it as a good book to have next to the toilet!