I had a summer job once, interviewing / surveying small hobby farmers for Environment Canada. Saw LOTS of hobby farms..
If they have a good solid 2 Acres (plus) of good grass field, I would get a beef heifer or steer. Buy at less than 1 year old, after all antibotics and shots are done, raise for 2 years, slaughter.
They do not scream like goats, are easy compared to sheep, do not need the daily attention of chickens, maybe even easier than pigs. No problems usually with predators, but you do need a strong fence, wind shelter, can't completely ignore them. Your parents are already used to large animals, anyway.
With good winter feed/hay, water source (vitamins) and salt lick, they need very little attention during the week, and let you go away for a couple of days. Self feeding in the summer on the grass. The best part, is like a pig, they can be a cost savings in terms of food prices.
Problems / costs are for rare --> annual vet checkups (and you need to validate feed is adequate), animal getting out, difficulty in finding slaughter facility (but only every 2 yrs), near trailer to move.