I own a 99 Blazer and bought a Coachmen Apex 151RBX that has a GVW of 3890 1 year ago. We're already upgrading our tow vehicle because "The RV dealer said we could tow it". We got camping fever during the winter RV show last year and bought a hybrid that we didn't really want but it was the only non-popup that would fit our tow vehicle.
Please check the RPO sticker on the back of the glovebox door. It will be a white sticker with a lot of 3-character codes in alphabetical order. The codes you need to be aware of usually start with GT(x) this will be the Regular Production Option code for your axle ratio.
As I have done a bit of research on the Blazers, the 5000# tow rating is with the 3.73 axle. Most came with the 3.42 to increase the mileage. If you have the 3.42, your tow cap I believe is between 4000 and 4500.
If you go to GM RPO Codes - Axle & Ratio Identification - Sierra Gear & Axle
with your GT- code, it will tell you what your axle ratios are. You want to see a GT4 for the 3.73 (there are others, but the most common for the Blazers are the GT codes)
As stated above, GM rated your Blazer with a full tank of gas and a 150# driver. Above that, you have to start subtracting every pound of driver, passenger, cargo, weight distributing hitch, other vehicle accessories, cell phones...
My family, dog, and gear that we didn't put in the trailer caused us to be over tow cap once we hooked up to go camping.
Tow rating 4500 (guessing as I have the 3.42 axle)
Trailer GVW -3890
family (4) - 870 (we're big folks)
dog - 50
WDH - 75 (BlueOx SwayPro)
Over tow cap 425#
Of course, this is assuming that we haven't overloaded our trailer.
This doesn't include any of the gear that we put in the Blazer either. Bikes, Portable DVD player, DVD's, pillows, cooler...
I haven't been over a CAT scale with my rig yet. But I'm sure the weight police would ticket me.
Now, living in SE Michigan, there aren't a lot of hills that would give anyone trouble. However, even with the gentle rolling terrain, we could tell that the Blazer was struggling a bit. I was ever aware of the barn door behind me. Crosswinds, while it didn't initiate sway, did blow the entire rig sideways. Also, while following semi's, the turbulence was enough to make me nervous and grip the steering wheel a little tighter.
We just acquired our new tow vehicle. A 1995 Chevy 2500 Suburban with a 7.4L gas engine. Should be able to haul 10,000 with it and not have to worry about the tail wagging the dog. This will also allow us to get the trailer we really wanted. Sorry it's not a FR product but my cousin's Jayco 26bh is a really nice rig.