i have a 2810 and run a 5' brush hog works great, spend the extra money for the slip clutch. cant tell you anything about a tiller as i am looking to pick up a used one. my dealer says king kutter at fleet farm would be fine and thats a 6'. keep me posted on the tiller.
is your 2810 a hsst or gear model...also have you been satisfied with the performance of the machine? I'm trying to stay in this sze for manuveabilty..
I'm doing fine with a 6" bushhog on my 2810HST. I've seen where some have posted that might be too big but I suppose it depends on how fast you're trying to go and what you're trying to "hog'. My thinking is you do want to be wide enough so you can cut along fence lines and buildings. As Glawall mentioned, a 66' would probably be a good fit. The only time I've even slowed my engine down is once when I was in thick weeds and run aground (an old terrace).
As for a tiller, I don't have one so I can't say. I've never used a tiller and don't know if they are more or less demanding than the "hog".