10 year old tires don't bother me so much as tubes in modern radials. Especially if they are tubless construction radials. Seen too many fail in the last 20 years in the tire business. I would look into getting a set of matches 16" rims all around. 16x7 with a 3.5" backspace will fit fine. Being a 3/4 ton, I would suggest a 215/85/16 or 235/85/16 E range, 245/75/15 would also be fine, as long as you go with the same load range.
