I think I'm in agreement with your analysis. It looks like the L1045 has no car-width shoulder (or much of a shoulder at all) and there are some nice alternate routes that wind through in the same general direction without much disruption from stop-signs at intersections every 500-800 feet. In that situation, as a cyclist I would not be riding on the L1045.
A few hours later, I would like to emphasise a few things:
1. I am not saying "Don't ever use roads". Sometimes, I accept that road use by cyclists is unavoidable.
2. I am all for more money spent on bike roads and -lanes, both for upkeep as well as for building new ones. More good bike roads means less bike traffic on standard roads, mean less dangerous situations.
3. I do not hate cyclists. I just have been in situations that became incredibly dangerous because cyclists slowed down traffic considerably (either because they had low visibility, or they inspired other drivers to dangerous overtaking attempts, or because they acted in an unpredictable manner (e.g. by not signalling or not following stop signs/red lights, or sneaking up from behind at a traffic stop and appearing out of the blind spot).
4. Some car owners are assholes and do stupid things to annoy you - much like some cyclists may act less than gentlemanly. We need more street laws enforcement to get either of these groups under control - these groups are those that make their supergroup problematic to the other road parties.
In short: Be considerate, be responsible, be visible (high-visibility clothing is worn by construction workers on road locations for a reason), be predictable. Use designated lanes/roads if available. Even if you may be technically in your right, do not demand it if the situation could be unclear to other road users - chances are they have a lot more survivability than you have if things go wrong.
And for god's sake, there's no reason to use a country road as a bike sports racing track during rush hour.
