Dave....before I set to buy herd there are a few things that I would check off my list.
1. Facilities...fences, pens, chute, bunks, trailer, barn, water, electricity to the places that needs it (up here we have to use tank heaters in winter). Nothing like turning out the cows and watch them go for a walk over to the neighbor's wheat field through what looked like a good fence.
2. Find a mentor...really important...and make some friends that raise cattle in your ares, most folks like to talk cows with almost anyone who talks back.
3. I agree with Preston39...he dispersal sale will be the best source of quality animals, you can get the history and be able to ask questions...and usually get to see sires and dams, a really big help when selecting your cows.
If you can spend some time with the herd in the morning and evening I wouldn't worry about working off the farm...they pretty much take care of themselves(good fences real important here). Buying the 3'fers is a great way to get started, you get to see what the cow's offspring looks like and have saved the trouble of finding a bull or AI(chute needed here).
Have you decided on a breed or buying Xs? I wouldn't shoot my whole wad on a big herd right now, the market is pretty high and we should see the seasonal drop in a few months...could be wrong it could hold on high through to winter, never know.
Good luck....Dave Mc