You could probably find a way to have a bot account bump it, but I'm not sure if those violate the TOS. I know that Swollow had a bot for distributing keys for the post like/dislike forum mod. and idk if Idle had a bot attached or not.
idle's bot just stayed logged in, and all you need to do for that is do something every fifteen minutes, which would include refreshing a page on the forum
swollow's just sent PMs, and if I remember correctly it only did it when you sent a message to him first, which isn't so bad
but idk if you'd be able to get away with making a bot post publicly. in any case, there's no real reason you need to tell people it's a bot, soooo