Google's P/E is 30x. So, 30 times one year's earnings is reasonable. Do you expect better earnings growth than Google? Then use 50x or more.

If the new job is typical at-will employment, I'd assign a value of $0 to that.

Would they hire you without buying your webiste? Would they buy your website without hiring you? That would help you value each component of the offer.

$200k now is better than $20k/year for 10 years, because you can invest that $200k. The question is the relative value of investing in the stock market, vs investing more in your product.