Welcome Gerben en Ilona.
As you have found out your Eriba does not have a large onboard tank and as such it will not have a hot water heater.
I fitted a large tank and electric water heater on a Familia 310Gt back in 2011. You fill the tank from the outside through something resembling a petrol filler cap. We use a cheap watering can and this is a lot more convenient than the small tanks you will have under the sinks The job is fairly straight forward if you are competent and organised at practical tasks. Fiamma do a suitable tank that is readily available and the TrumaTherme water heater is your best option for the price. If you start going gas/electric combination it will be expensive. Your taps are also going to be a significant cost as those in your van at present are not set up for hot and cold water.
Thule do a nice quick to deploy wind out roof awning, but I'm guessing this would be about Euro 1500 fitted. The Fiamma Caravanstore zip bag canopy is a nice quality option but fowls on the door and is annoying. You can get around this by gluing and screwing another awning track about 120mm above the existing gutter/awning track. The other option normally taken is the excellent Isabella Shadow canopy. This can be up and secure single handed in 5 minutes.

Best of luck in your modifications and please feel free to ask lots of questions.

Colin

Hi Gerben en Ilona and welcome to Eribafolk
Randa

Hi again Gerben en Ilona.

I think the most popular Sun/Rain Canopy on here is the Isabella Shadow (as Colin Motters has mentioned above). For a Triton you'd need a 3,000 metre long one to give you the full habitation length of the van.

The only drawback and presumably you're quite tall, being from the Netherlands is that the maximum height for the Isabella will be the same height as the awning (tent) rail above the Eriba door.

Many folk have gone on to adapt their Shadows to make them a little more comfortable like adding a third adjustable pole and extra storm lines.

https://www.google.com/search?q=isabella...5KnWpGTYw4,st:0

Randa