I went through the solar / battery design build process last year for my 30’ Flying cloud You could buy and install the charger/inverter now and add the solar with new batteries later. I would recommend using a pure sine wave inverter. They cost more but there is less chance of your electronics going wonky.
Based on what you have described (no microwave or blow drier, minimal TV) you can easily get by with a 600-1000W inverter. Remember you only need the inverter for AC power requirement. Your 120V AC needs may be driven by your home office equipment PC’s printer ect. You might think about adding a few 12V
outlets if needed to handle all of the phone and other small rechargeable stuff. Its more energy efficient in most cases, reduces the need for AC and the size of your inverter.
Important things you need to help you figure out what you need:
1. Average daily 12V
DC Amp Hours will you consume per day
2. How many days power with no solar (consecutive rainy days)
3. Maximum momentary 120 V AC Amps to size your inverter
Remember when sizing the system 1 amp 120V AC is approximately 10amp 12VDC.
For the Solar Panel install there is no need to drill holes in the roof and potential places for leaks that come with them. . AM Solar sells the mounts and adhesives. I have over 6000 miles on mine no panels have blown off or come loose.
My installed AM Solar system :
SunRunner Signature 40/4/Pro Core
4 GS 135W solar panels
Magnum 1000W Charger/Inverter
4 Lifeline 6 CT Batteries
New low profile vent covers
The wiring is sized for up to 800W should I want to add panels in the future.
System is providing anywhere from 35 AMP hours to 5 amp hours mid-day depending on shade and the weather outside. Happy with the system performance. BTW I have no relationship or vested interest in AM solar just a happy camper.