Welcome to the WtW - That 140 watt Zamp solar panel is way over priced.
With regards to old school lead acid batteries, here is my best lead acid experience. I hope that it is not too much info.
Before upgrading to lithium - I had a deep cycle AGM lead acid battery that lasted 6 years with proper care. Proper care means that I never discharged the battery below 12.1 volts and when not in use, I kept plugged in to a battery maintainer. Whether or not it was as good as new after 7 years - all I know is it would still power my portable cooler style fridge for over 24 hours even after many years of use with no problem. The secret weapon was I had the AGM battery encased in a now obsolete ArkPak 730 charging unit.
The ArkPak has a downside in that its maximum charge rate is about 6 to 9 Amps - which is about 75 to 100 watts per hour. - which means slow. In its favor, the unit is able to step up whatever voltage that is received from the truck battery to about 14.1 volts during its bulk charging stage. After that the ArkPak output provided 13.7 volts at reduced amps for a very long topping off cycle for that last 10% of charge. From there it maintains a 13.2 volt float charge.
To conclude - my biggest gripe with the ArkPak is should the AGM battery become depleted down to 12.1 or 12.2 volts at rest - the full DC to DC charging process could take up to 6 or 7 hours of driving before it reached its float stage. My second gripe with the ArkPak is with a Group 27 AGM battery, the unit is monstrously heavy.