3500lbs vs 5200lbs trailer question

Good morning thanks for help in advance. Looking for advice on towing. Wondering the difference in real world towing difference of 1800 pounds.

Looking at 2 Toy Haulers. The question is for 1800 pounds more we get a lot more trailer. How much will I notice the difference in towing between the 2. How much more mpg will I loose with the heavier trailer? I am a fan of keep it simple. But don't want to be kicking myself for not buying a little bigger.

Tow Vehicle 2011 Chevy Express 3500 Van.
9600 tow limit no issue
16000 combined weights no issue

99% of time 2 Motorcycles (250cc) 230pnds each, 3 people.
1% of time NO Motorcycles 5 People. Just camping

2017 FOREST RIVER SALEM CRUISE LITE 211SSXL
uvw 5300
Hitch 890
GVWR 8890
28ft long

Pacific Coachworks 18sle
uvw 3500
Hitch 530
GVWR 7500
23ft long

Thanks Bill