Do you need a laptop at all when you're away? If not, consider an ipad.
We have an ipad which is great for use in the van, takes up little space, recharges on cigarette lighter type socket (plus regular 3 pin, or you can get a
solar power packs etc. also). Bought the ipad 2 as soon as the newer one came out, so reduced in price
We use it for internet surfing, watching movies (downloaded), and watching TV (iplayer), reading (downloaded books/magazines/newspapers etc. - saves space on books!), downloading maps, satnav, chess, Monopoly, and all sorts of other things! Has access to thousands of app's which cater for whatever your needs may be, including 'Pages/Numbers/Keynote' package (similar to Microsoft 'Office') if you ever need them.
Don't know if the program you mentioned re mapping has an ipad app, but there are many out there so sure you could find something to suit. You can also get apps which translate languages if you're abroad, find campsites if you're not wildcamping etc. etc. etc.
We use it tethered to an iphone (unlimited data on 3), so we also have free internet access wherever we go (unless the signal is very poor), so no paying extra for internet access at campsites or similar, and the connection is secure (as any mobile connection can be!).
You will not have as much storage on an ipad as on a new laptop, but sounds like you probably don't need a huge amount anyway? However there is a free automatic (online) backup system called icloud which means your photos & data is all stored safely in case you do lose the devise (don't like to think about that one!). You can also use an external hard drive as suggested too. The screen resolution is brilliant (sorry not a technical term!) both for viewing media/films etc. and for reading, and you can adjust the print to any size you like using simple swipe movement on screen. It's very light and packs away really easily (don't know if you have a safe on board your van, but depending on size you may be able to lock it away),
battery life is good too, definitely comparable if not better than laptop.
Don't know how much you're considering spending, but ipads are selling around the same as mid range pc/laptops, and we've found it so much more intuitive and useful than taking the laptop away with us, also there are second hand ones out there which bring cost down further. We're very happy with ours for traveling, but you'd need to check out the spec yourself (or borrow one for a weekend if you know someone who wouldn't mind a lend!) and make sure it would meet your needs. Hope this helps. Happy surfing!
PS (The main reason we like it is it's so easy to use and you don't need to know anything technical - the older I get, the less patience I have with 'getting things to work'! Ha ha!

c: )
PSS! (If you go for a laptop, you might think about getting it from QVC? Only because you can buy an Acer or similar, get it sent to you, and then use it for a whole month - if you don't like it you can just send it back and get a full refund. Obviously you pay cost of P&P, but we often do this, as means you can really use it properly and find out if it suits, and if it's not exactly what you want, there are no arguments about sending it back/refund etc. Works for us!)