If I put 200lbs of the pop bags on one side of the boat and then 200lbs on the other side so the weight is evenly distributed could I tow with the bags in the boat or do I need to remove the bags each time. I'll be towing around 70 miles each way.
If they are even front to back and side to side it should be ok. I there is to much weight in the back it will start out fine but when you get up to speed it will lift on the tongue and it can get bad really fast.
I tow with 560lbs of pop bags all the time with no problems. depending on the trailer....you might want to spread them out over the axles. I personally spread them out around the boat. It depends if your trailer is tounge heavy and it depends on your tow vehicle as well. Just experiment and you'll be fine....
i have been towing with 400 lbs of pop bags on numerous trips and have not noticed any issues. as other have stated, i had them spread out all over to sprad the weight around
I used to tow my tristar 190 with about 1500 extra lbs in it with no trailer brakes behind my 98 Isuzu Rodeo. I would tow it from Henderson to Lake Mead. Gave me some nightmares about a time or two when I had to stop fast. It would weigh down the back of my car and the front tires wanted to lock up if you had to brake hard.
I now have an 00 Yukon and I wouldn't worry about it, but still trailer brakes are better when they actually work.
As for 500lbs, I wouldn't worry about it. Especially if you have a full size tow vehicle.