What do you have now? Probably 3.73 or 4.10 (or 3.55 on some 4.0's). If you're going from stock 29 inch to 35 inch tires, (considering the 29 inch factory fit), then you're going up about 20%. To keep your "power" and not strain the drivetrain, gear up to match.
If you have 3.73 or 4.10, go to 4.56 (4.10 are already pretty high, so 4.56 should be fine).
If you have 3.55, go at least to 4.10 -- although 4.56 is a good choice if you're not too concerned about a slight drop in mileage and higher revs on the highway.
Overall, I'm in favor of 4.56 on any Ranger with 35's. It seems to be a good compromise between power and speed, and keeps from stressing a drivetrain that is not overly strong -- particularly the transmissions. I'm running 4.56 so I may be biased, lol.
If you balance the gear change almost exactly with the tire size change, your speedometer will be pretty close and you won't have to recalibrate.
Some guys even run 4.88 -- but that's pretty extreme for a daily driver I think. Just my way of looking at it though and merely opinion.