I've decided to tick off the cranky nations from my list of countries and autonomous regions to visit (quite similar stuff as seen done by DanielW, ironmanjt etc.). It's probably more rewarding to end with something like Monaco, sipping a vodka Martini at the casino and recollecting how that "hotel" in Freetown was "slightly" shabbier than this etc.

Furthermore there's one very plausible reason: as long as I'm single, it's just way easier to visit certain types of countries as a harmless solo travelling male. No need for a marriage certificate for a shared hotel room (Iran) or having to think more than usually about local customs. Plus there's a plethora of security concerns.

I've so far read extensively about visiting Saudi Arabia in the current diplomatic circumstances. I also called the visa office of the embassy of KSA in Helsinki (only the local Iraqi embassy is more posh than theirs, thanks to Saddam). At that point I wasn't aware of using a transit visa to get around the tourist visa curfew.

Which of these plans is most likely to work?

A) Book a return ticket to Dammam, have a hotel reservation in Bahrain and claim that you need a transit visa with land access as you either rent a car from DMM (there's at least Hertz available) or take a cab. Should be able to stay at least one night in Dammam with this plan.

B) Book a return ticket with SV via JED with a layover that's over 18 hours. Would prefer a proper stopover for 2 nigths, resulting in the need of a 3 day transit visa, which I've seen someone being able to get on FT or a blog, can't remember who. On the inbound leg I wouldn't mind staying airside, if I was able to get my transit stopover on the outbound leg.

Any thoughts on this?

Both will be hit or miss on whether the respective embassy and generally currently issue transit visas.

I would suggest you check with one of the visa agents services who process for the embassy to see what options they have for you, as they are quite aware of what is available/practical and what is not.