What I do when I travel is bring an Android tablet (see below) with an OTG cable. Then I have a portable hard drive and a large USB thumb drive which I store in separate locations. I leave the hard drive in my luggage and carry the USB drive in a ziplock bag with me always.
The OTG cable allows me to connect a USB hub to the tablet, and then I plug a card reader and one of the storage devices into it and copy the photos off of the card. Then I switch storage devices and repeat before I format the SD card in the camera.
The Android tablet also doubles as a navigation device, as I load offline maps to it with MOBAC (PC software) and OruxMaps (Android app). Since the tablet has a cell modem and is GSM unlocked, I can buy SIM cards in other countries and use it as a phone (so big on my face) or a data device.
I like this Galaxy Tab 8 because it's cheap, and unlocked, and has a micro SD card slot. Most of the Tab 8s do not have the ability to use OTG cables, but this one is different, as it has a cellular modem and OTG support (source: I use it). But alternately, you can use any Android cell phone or tablet you already have as long as it supports OTG cables. My Note 3 works great. That would save you $200 if you already have one.
Here's a good, cheap OTG cable. It's good because it doesn't have a fat plug, so it works with most cases, and it comes out at a right angle, so it's less awkward. Bonus, it comes in a pair, for backup's sake.
BOM:
128 GB USB drive ($30)
1TB hard drive ($60)
Android device with OTG capabilities ($0-$200)
OTG cable ($6)
USB hub ($7-- maybe add a second for redundancy)
Card reader ($7-- double this too?)
Rmaps or MapDroyd, but these apps aren't offline navigation, only offline maps which will show your location via GPS.
MapDroyd: Only uses OpenStreetMap which I think is better in Europe. Downloading is streamlined in the app; you just download the country as a whole.
Rmaps: A little more complicated, and you also need to use Mobile Atlas Creator, but you can also choose whichever map source you'd like with that software. The program can be a bit confusing to properly use so if you need help just PM me.
I was in the Dominican Republic in February and used Rmaps with downloaded GoogleMaps data when we drove across the island. It worked well, though I neglected to get enough detail in the cities so we ended up driving in the direction of the main road in random directions for about ten minutes, then all was good.
I use the "MAVERICK" app because i find it easy to navigate for what im looking for. You can also use it in combination with "mobac" to create custom offline maps that are preloaded. Mobac has access to US geological survey maps which would be an added bonus for me if they also had access to a canadian equivelant.
Heres a link to mobac for anyone interested, Theres a list of devices and apps yhat its compatible with http://mobac.sourceforge.net/
You can apparently get the mobile atlas creator, select MBtiles and download the tiles. If you want to use the OSM vector tiles (offline) as a source instead of thrashing the public servers, look into the README.HTM#FileBased File that comes with the download. I haven't looked deeper into this, but that should do the trick.
The program doesn't really cater to offline use as you can see. I know this is not what you asked for, but maybe to make things easier you could QMapShack a try. It is a little cumbersome to work with the first time and I don't know what exactly you are looking for, but it is was easier to setup for offline use and has good documentation.
While contacting the provider is often the best option, You should know about Mobile Atlas Creator You can use it to download tiles from many providers. Always remember to follow the T&C of the Service provider.
You can convert them to the GPX format, and then use MOBAC to create your own maps. Or, if you have a smartphone or sufficiently advanced GPS, you can put the GPX files directly onto that.
I used GPX tracks on my smartphone while biking in Norway a few years back, and I think it worked pretty well.