@Scoutrover13 - sorry, did not see your question to me. Feel free to PM if you have more questions.
This is my poor man’s power supply. I use this deep cycle battery in my boat so am already set up with a nice charger. This inverter clips to the battery and provides 2 power outlets as well as a USB port to charge or operate USB devices. The inverter shown is a 750 watt unit but mine is smaller, like 300 watts but powers the few items I ever take (primarily the pump on our air mattress). I also use this setup to power my electric yardwork tools - easier (for me) to move this around in my yard wagon than unwind and rewind that 100 yard extension cord that I hate.
There are plenty of different brands of batteries and some have more capacity than others. If you google them it’s basically like debating religion where everybody has strong opinions on which brand batteries are good and bad. These Walmart ones are just fine. Like any deep cycle battery they all last longer when you CONSISTENTLY put them on the charger when you return from a trip. In a pinch you can also use a regular car battery if you have an extra one sitting around, just only use it for short times like running an air pump for a few minutes. A deep cycle is better though as it is intended to be run a long time and discharged lower than a regular car battery should go. Same for the inverter in that there are many, many different brands. If it was me I’d just get the $30 Walmart one and take it back if it dies.
The battery is heavy but you are bringing a lot of juice. You can get lithium ion deep cycle batteries to save some weight but they are 2 to 3 times the cost. To some folks it is worth it. Some google searches about deep cycle inverter box will find you lots of DIY builds where they do similar and even fancy stuff.