I wouldn't bother with a shower, uses too much water and creates too much condensation and possible damp problems. Loo is enough.
Think about how you will use it on site, if you have an awning you can set hings up in there and not have to secure it if driving off. Everything in the van will have to be secured before moving. Also beds have to be made and unmade to use seats and seatbelts, but you may have to do that anyway to use dining area.
If you are likely to just park up and stay put for the duration then not as much hassle, or useing bikes to get out and about.
You will have double, tax, insurance MOT etc,
If you already runa biggish car then it could tow a caravan.
I have a small camping van and hope to get a small car again. decided against buying a big car for towing and a caravan.
Love my camping van. No not a campervan. It has a removable cooker that can be set up in the awning along with table and all that and a small portapotti, no toilet compartment in van. My awning is big enough to stand up in (unlike the van) and is a driveaway (stands up on its own. Beds doesn't have to be totally derigged to get to the 4th seat. 3 seats in front so if just me and DP or me and 2 kids bed can stay put.
My DD sleeps with me and DS on a big cushion across front seats. If away with DP they will sleep in the bedroom compartment in the awning (hopefully) or we will and they will have the van .