Solar system

First calculate the power consumption per day usually the electrical equipment has a sticker with Volt and Watt rating. Example 3 hours TV at 100W, 4 hours computer at 50W, 6 hours lamps for 30W ..... this gives you the Watt-hours of electric power used per day.
Let's assume you need 1000Watt-hours a day. For an average 3 hours of full sunshine equivalent per day you need PV modules for around 333 Watt e.g. 4 modules 12V with approx. 80-90 Watt (many choices available so take whatever size and dimensions fits best on your bus). A solar charge controller for 12V with 30Ampere, a 12V true sinewave inverter (better for computer and sensitive equipment, don't use cheap square wave or mod sinewave) for at least 600Watt or even  for 1000W (depends on how many load you use parallel). You can use also an inverter with charge function, so in case you can connect to the grid you can charge the batteries in case not much sunshine and heavy consumption. Finally you need a battery bank for 1000 watt-hours a day, with reserve for at least 5 days = 5000 Watt-hours. For 12 Volt system = 416 Ampere-hours battery capacity better a little more.
For light you can use 12V fluorescent lamps, so no use to run the inverter for this, maybe also the laptop computer can run directly on 12V.
Hope this gives a little idea how a ssystem could be designed.