Falco wrote:But I was wondering if there is a route navigation device that anyone could recommend?
I have a keen interest in this question, and have spent a lot of time looking for answers. If you do want to go down the digital route, here are your options:
If you're happy with just maps and no navigation then I'd recommend a smartphone loaded up with an offline mapping app. I have an iPhone and thoroughly recommend paying the few pounds for Pocket Earth, with which you can download maps of the entire world for use offline. It is based on OpenStreetMap and has a cycling layer as well as plenty of POIs (although these can sometimes be inaccurate).
For navigation unless you want to plan your entire holiday before you leave, you need a way to create routes whilst on the road. If you can guarantee internet access then a small tablet (or maybe even smartphone) can be used to build routes online via cycle.travel. You should be able to tweak the routes but the interface is designed for use with a keyboard and mouse so it's going to be painful; you wouldn't want to do it too often. Either mount the phone on your handlebars or transfer to a GPS device with offline maps (Garmin Edge / eTrex for instance).
If no internet access then you will need to build routes offline. The best software for this is Garmin BaseCamp which runs on Windows or MacOS. It can read and route using OpenStreetMap maps - just mark A and B and the software will find the best route between them, and you can tweak it to your heart's content. This requires a 'proper' computer, you can find Windows laptops/convertible tablets with keyboards and trackpads weighing around 1kg for approx £100 on eBay. When complete you export as a GPX and import onto your smartphone or GPS device as above.
An alternative to the above would be to buy a small Windows tablet like the Dell Venue 8 Pro (£75 ish on eBay) which will also run BaseCamp. The device is touchscreen only and BaseCamp is terrible without a keyboard/mouse (believe me, I've tried) but a cheapo handheld keyboard/trackpad combo can be bought from Amazon. Total weight would be around 500g at the expense of a more painful user experience compared with a laptop.
I really like digital mapping as it opens up so many quiet roads perfect for cycling that wouldn't be shown on a regular map. The biggest disadvantage is when somebody asks "where are you going?" it's much harder to show your route using a Garmin than with a paper map.