They would likely not argue if you set the declared value at $25K, difference in policy would be minimal. But be honest with yourself about the condition.

Can't rate a car without photos and hands-on, which is why appraisers are in business. A car could be all you mentioned above and still have critical rust issues or former collision damage or simply be degraded by time to a lower level.

Check NADAguides.com for a "book" value.