If you can live without a heated cab, I say go for it. If you even think you may want a heated cab in the future, you may want to wait. Do you really have to pay that much tax? Could you save paying the tax by buying from a private party? If you decide to buy it, maybe try talk them into a set of new tires. This will say you about $600 - $700 down the road. Get them now and mount them later when these tires totally wear out.
If I remember correctly, the 863 has a ROC of 2000#. Oak weighs about 59#/ft2, so you could carry a 20' 18” diameter log at the ROC. Two logs this size would put you at the tipping load. Pine is about 45#/ft2, so you could carry a 25' 18” diameter log at the ROC. I think this would handle you needs fine.