I have several virtual assistants I use that would fit what you are looking for. Some are based in Canada. I know you suggest that you are looking for US-based virtual assistants. However, I would consider that some overseas virtual assistants are quite skilled. The virtual assistant that I have used the longest and is by far the best is based in Pakistan. He is a vital part of my team and cares deeply about the success of my projects. He learns quickly and values the relationship which he shows through honesty and quickly letting me know if something is above his skill level.

If you are willing to go through the ropes posting a job, interviewing, and vetting someone, I would suggest Upwork (formerly oDesk). This is where I have been discovering most of the people I work with. However, it is extremely challenging to vet and decipher between quality candidates.

I hope this helps. I may have some virtual assistants that I have used with extra time. I would love to chat further, here is my Clarity VIP link for a free call. https://clarity.fm/lipmanb/vip/t