After some googling, I found a way to assign ALT+<number> to switch to datasheet view and to design view without looping through view modes. I added the Run and Design View commands to the Quick Access Toolbar. When I press the ALT key, I see the numbers related to my quick commands, and they are numbers, so I can use ALT+<number> to invoke the corresponding command quickly. In my case, I can run the current query I'm working on with ALT+5 and switch to design view using ALT+6.
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I found this idea on www dot microsoft-question dot com (can't place a link here - do not have enough posts yet).