Find out the gross weight of the TT, and then find out what the payload of your Tacoma is - look at the door sticker. It will say something like passengers and cargo weight not to exceed...
Where do you get this 6500 number? Is that the stated Tow capacity? It's not what the truck can pull, its what it can carry. Looking up payload your vehicle, I see there is a range of 865 to 1465. Payload will be exceeded before tow capacity, and towing a high walled TT is not like pulling a weighted flat trailer that is used to determine tow capacity.
When you get the gross weight of the TT, multiply it by 12% to estimate the tongue weight. Then subtract the estimated weight of the people and stuff you will be carrying in your truck. Then subtract from payload.
Notice the use of the word estimated. To be sure, Google Cat Scale, load up the truck for camping and take it to be weighed.