I like @Ruben C's solution as a good alternative to computer UPS, given certain implied requirements can be met by the "truck" and the premises and one's willingness to set up the configuration. In 10-inches of snow, it might be annoying to deploy.
Upon re-reading this thread, I can see that one option was missed -- job-site portable power tool supplies, such as (e.g.) Milwaukee make: https://www.milwaukeetool.com/Products/Batteries-and-Chargers/M18-Batteries-and-Chargers/M18-Chargers_Power-Supply/2845-20 (choosing a tool brand at almost random). These are likely somewhat heavy (M-18 is 28 pounds), but designed to operate in adverse conditions.
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small living room w/ limited seating
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