The simpliest explanation:
I. идти/ехать is a process. Literally - be going (by foot/by car). Я иду на работу - I'm going to work (now). Compare: Я хожу на работу - I go to work (every workday). And yes, we use ехать/ездить only if it's by car/bus/underground, etc., if the whole way is by foot, we use идти/ходить.
II. If we use infinitive we can say идти/ехать if we mean a single (non-repeated) action. Я не хочу туда идти. - I don't wanna go there (single action). Compare: Я не хочу ходить на работу. - I don't wanna go to work (not just today, but in general - meaning repeated action).
III. In 'when' clauses we use идти/ехать, because we mean the process itself again. Когда я иду на работу, я не отвечаю на звонки. - When I'm going to work I don't answer phone calls. (not sure continuous form is appropriate here in English, sorry if I'm mistaken). "Когда я хожу..." would sound a bit unnatural. But in the past tense things differ. We use ходил/ездил in case we don't mean a single action, but all those actions together. Когда я ездил на работу, я никогда не видел этот дом. - When I went to work I never saw that house (I went to work lots of times of course). The opposite, we use "шел/ехал" if we mean a single action. Когда я вчера шел на работу, мне перебежала дорогу черная кошка. - When I was going to work yesterday a black cat crossed my way.
And yes, with любить we usually use "ходить/ездить" because we mean those actions in general but not a process. In the accepted answer there is "я люблю идти по ночному городу..." but for me it sounds unnatural (I'm a native). I'd say "я люблю ходить по ночному городу и наслаждаться тишиной". And yes with some idiomatic expressions like "идти на рожон" we use only this form.
Your #2 item: correct, because you don't mean here a repeated action in general.
Your #3 item: Мы ЕДЕМ на море - only if we are doing it now. Otherwise Мы ЕЗДИМ. The same is for the second part of your sentence.