Albany NY to Atlanta

You might also consider taking NYS Thruway I-87 south to I-287 at NY/NJ line, then I-287 to I-78, to I-81.

I did this trip this past June on the way to Nashville. The only issue is that it seems all of the roads in Pennsylvania are a little bumpy.

From my experience, I set the cruise control at 62mph which is the sweet spot for my truck and with fuel & food breaks from point A to point B, I averaged 50mph.

I usually go I-88 to I-81 when heading south from Vermont. As I recall, I-88 has sections that are concrete and so have periodic expansion joints. Otherwise, it's a nice route, with some truck traffic and hills but nothing unmanageable—and the scenery is pleasant.

From Albany, I-87 to I-95 is another other obvious route, and I very much do not recommend that. Baltimore and DC, in particular, are horrid to drive through unnecessarily.

Is the three days including the day you're picking up the (new?) RV, or is it three whole days for travel? If you're buying it on the first day, don't count on getting much if any driving in that day, between paperwork and walkthroughs/checkouts and so forth. (If it's literally just picking up an RV that you're familiar with or already own, that's a different story.) It looks like it's fifteen hours or so of driving to get to Atlanta from Albany, quite possibly somewhat more in an RV.

Avoid the DC area if you can. Traffic is very bad. I81 or US301 are good bypass routes.