gearing and axle questions

[snacob14]

I'm running a 285 rear on a 20" wheel. I've got an 87 w/700r tranny. My rearend is currently either 2.73 or 3.08, I haven't gotten under it a checked yet. My question is what are you guys running for gears on this size tire. Overdrive is kinda useless unless I'm doing 80. I'm thinking 4.10's would be good, but I don't want it to be screaming down the highway. I was thinking it would cost quite a bit to do the gears, even if I did it myself I'd be 300 deep in parts. I may just look for a rear already geared or even a 9inch if the wms width was the same. What are you thoughts.