Here's the deal: when I'm off the bike, my goal range is 90-120, based on 2-hour postprandials. This is not to say that I never pig out and go way higher than I should, or that I don't rebound high after some things, but I'm very uncomfortable seeing readings higher than 110-120 for more than an hour.
When I get on the bicycle, I average 12-13 mph on the flats, closer to 10 mph when I have to worry about hills (my climbing sucks and I'm often-enough walking the vehicle uphill).
For most shorter rides (under 20 miles round-trip) this isn't an issue, but for longer rides, it is.
My two issues are electrolyte replacement and in-ride nutrition. If I ignore electrolyte replacement, the second I stop my blood pressure will drop low enough for me to feel faint for several hours -- but if I take in any electrolyte fluid (even sugar-free, carb-free ones), I will go up beyond 150 and stay there. Similarly, since my bg's don't drop into an obvious "you need carbs" zone (under 100), if I pay attention to what my legs are feeling and what the HRM is reporting (heart rate, calories burned) and eat pretty much anything, I will go up somewhere near 200 and settle back into the 130's for the duration. Because I have to monitor sodium (I'm on blood pressure medication) and protein (I have been treated for iron-deficiency anemia), I tend to favor Luna Bars and Larabars. I've tried Sport Beans once, but not in a manner to draw any conclusions; ditto with an Accelerade gel this past weekend (issue: not testing frequently enough to catch behaviors).
Other than saying, "heck with it -- I'm burning through the calories, I'll ride high and be high for a few hours afterwards" are there techniques or suggestions I should try?