If you want to charge cellphones and laptops, getting foldable solar panels to charge a battery bank, like a Jackery, should be pretty simple and wouldn’t require much, if anything, in terms of doing your own electrical work.
If you want something bigger, or to do your own electrical work, that can get a lot more involved, depending on the scope of your project.
Tbf on the electric boiler, it’s probably better to have that than a gas boiler, in terms of CO2 emissions. It depends on how clean the local grid is. The incandescents make no sense though - LEDs are so much better. Even if you don’t care about using less energy for environmental reasons, upgrading the lights would save enough money in energy costs to pay back pretty quickly