What if the Buddha wasn't a prince? If the Buddha wasn't a prince would his outlook on life been different? If he was a farmer looking after his land, feeding his family for example, would he have simply left his responsibilities behind to attain Nirvana? 

If he was the father or husband of a family that needed him, would he have left them?

The purpose of the question is to understand that the Buddha left his family who had all the comforts in life. He didn't need to be concerned with their welfare since they would be provided for. How does one relate this lives of those who do not have these safety nets?
To the first few questions the answer lies with parami/paramitas. These are the perfections which someone who made a vow to become a Buddha will have to develop to perfection for countless aeons. So a Buddha is someone who have trained for aeons until he is perfect to re-discover dhamma and teach. So his last birth will always be of a high social class.

"How does one relate this lives of those who do not have these safety nets?"

Develop the ten paramis and situations in life will change in such that one may have the opportunity.

In the Pāli canon's Buddhavaṃsa[3] the Ten Perfections (dasa pāramiyo) are (original terms in Pāli):

Dāna pāramī : generosity, giving of oneself
Sīla pāramī : virtue, morality, proper conduct
Nekkhamma pāramī : renunciation
Paññā pāramī : transcendental wisdom, insight
Viriya (also spelled vīriya) pāramī : energy, diligence, vigour, effort
Khanti pāramī : patience, tolerance, forbearance, acceptance, endurance
Sacca pāramī : truthfulness, honesty
Adhiṭṭhāna (adhitthana) pāramī : determination, resolution
Mettā pāramī : loving-kindness
Upekkhā (also spelled upekhā) pāramī : equanimity, serenity