State Hwy 21 is also called Blanding Blvd in Clay county and is one of the busiest roads in the county. It is 3 lanes wide each way from Middleburg into Jacksonville and the stretch from Middleburg to I-295 is wall to wall all three lanes during the day. A million stop lights but they are timed pretty well, It looks like you may be an early riser and if you can get to Middleburg by 5:00 a.m. it wouldn't be too bad. There is no problem taking a big rig through it other than the traffic. There is a Raceway on the right just as you are leaving Middleburg that we used in our 40' MH towing a Jeep.
There may also be a lot of construction along 21 from south of Middleburg until you get past the turnpike. Clay county is booming! Otherwise I would suggest getting on the new turnpike (Hwy 23) just north of Middleburg to I-10 to I-295 to I-95. It will cost you a few dollars but is worth it. We have found the drive up 301 to be very pleasant though you do go through a few small towns. If you are taking I-295 to I-95 be aware there is a lot of construction near that intersection so make sure you are in the left lane of 295 a mile or two before you get to it so you will not have trouble getting over.
