Solar stills do indeed work, but as seen on the lost at sea episode of surviverman they only produce a very small amount of water and you must remain stationary to use one . assuming you were at a base and were not moving on a solar stills could supplement your water supply but you would need a number of them. the best thing you can do for water is to obtain detail maps of areas you would wish to bug out to and them ascertain where you might setup near a stream that is too small to attract much notice. recon the areas in advance and locate water sources not noted even on detailed maps. agricultural areas often have stock ponds and wells for irrigation that could be tapped. kytadine camp filters are available and use gravity to filter water through several filter elements eliminating the need to pump water through a small unit but these have the drawback of being sort of large(about the size of an office waste paper basket) and they ,as do all filter systems benefit from prefiltering through something like several layers of tightly woven cloth to remove gross particles and silt. you should also consider chemical water treatment as there are several different types and these are very compact to carry but will not clarify the water so again prefiltering would help. if you know where you will set up your base you can cache water along the route and at the base. water will not spoil like milk or other drinks but it can get stale due to contamination and can be treated to restore it to potability. unfortunetaly water is one of the key limiting factors in survival as you can only live for about 3 days without it and in hot or cold climates or when working hard it takes even more water to survive.

water from trees ? be warned - it tastes DISGUSTING , i mean really foul

yes water from a lot of sources can be foul tasting but once the water has been collected and processed through a filter system it's unlikely to have any unpleasant taste and in a survival situation given the proper equipment i would not pass up a mud puddle.