My advice is to see how you go without them. Your motorhome was designed without those things and has been used without those things up till now. So you ought to get by without them to see how it goes.
Refillable gas makes life a lot easier: you can top up at will, so no bottle changing, no decisions about whether to swap now and waste some.
Yes it will make the gas cheaper, but the payback period is measured on many, many months of use. If you might change vans, a refillable bottle makes sense. If you plan to keep the motorhome for a while, get an underslung tank.
Satellite TV?
Why not stay at home and watch TV, go away and don't watch it? Or get programs from the internet.
Solar Panel? If you have a problem with running out of power, start by fitting LED bulbs. You shouldn't need
solar panels.