i am more or less the same phisical as you and i have a big wheel cr80. (the same as the crf150R)
while i really, really like this bike i have to recognise it´s a mini bike and sometimes i feel it just plain small... :nod:
that said the crf150R it´s a race bike. has lot of power, great suspension but demands lots of maintenance and wears out fast.
while a crf150F is a trail bike it might be underpowered to go to desert. suspension not the best for that also... you can kill this bike in a few weeks.
honda xr series, be 250 or 400, are great trail bikes. heavier that the 150 but great all round bikes. they are cheap and last very long, even when abused.
another option the crf250X. they are the new xr´s... look around and see what you can get on your price range. :cool: