i had a 2.8 y61 trol and it was a good bus but 24mpg on a run and less than 20 around town.. the older y60 can get you around 30mpg on a run but these are rusty as hell so have a good look around..
for your money you are looking at an older rather than a newer y61. the 2.8 is better than 3.0 as the 3l breaks, often. i think in 3l you need newer than 05 or you need to save a couple of grand for the work doing when it goes kaput..
then it will kaput again if you are unlucky..