I agree that it's possible for outdoor spread to occur when you have inconsiderate folks obstinately ignoring guidelines (like the Rose Garden event). Outdoors with 6' separation for sustained exposure, or even brief outdoors close exposure (like passing on a trail) seem to be pretty safe activities even when unmasked. Unfortunately there hasn't been a lot of real research on the idea, outside of that one discounted theoretical model. So my own continued trail and post ride activities are all I have to go on.
The other thing--I've never really been worried about myself or household. We're generally healthy folks who take reasonable precautions and follow the current guidelines to the best of our understanding. I've been far more concerned with becoming an unbeknownst spreader, and then infecting the more venerable, including some with whom I work closely. But I think the good news here is that by April, even though we will not have achieved heard immunity (though survived infection + vaccination) I do think it is likely that the most venerable among us will be vaccinated by then, alleviating my primary concern. I will, however, continue to take reasonable precautions until I'm vaccinated as well.