For almost a dozen years now I've been using a Garmin eMap as my cycling computer. It includes a basemap that shows about the level of detail as state highway maps and can also be loaded with far more detailed maps of specific areas (either from Garmin for $$ or OpenSource for free). Does everything I want on a bike which is why I haven't upgraded. It's been discontinued for years, but I see some places still sell it for about $100. Runs on two AA batteries and I use NiMH rechargeables that last about 15 hours per charge. The handlebar mount is optional and costs an extra $5 - I just use a few rubberbands to hold it on top of my stem. Works great for recording where I go and I use a website that automatically locates any pictures I take along the way by synching the picture timestamp with the GPS tracklog. Here's an example from yesterday's ride:
http://www.everytrail.com/view_trip.php?trip_id=964647

I'd also recommend other Garmin hiking models as being much less expensive for what you get than their cycling-specific models. Also the hiking units generally run on AA cells which make it far more convenient when touring since you can carry as many as you'll need (and in a pinch you can always find AA cells along the way).