I didn't think that they saw themselves as "down south" in Devon but you should certainly visit the area to dispell any misconceptions.
Normally relocation packages will help you to get a property that is similar to where you are at the moment so they might pay or lend money to pay for estate agent and solicitor fees as well any difference between the price of what you are selling and what you are buying. Removal costs, costs of buying out phone/cable/etc contracts are often expected. I doubt that you'll get financial assistance with a plan involving contingencies for "incase it doesn't work out" though.
If you have children, you should consider the implications for schools and so on. It would be best for their education if any move took place during the summer holidays so there could be extra costs if you were to move now and they were to move in a couple of months.
Other family ties should also be considered including, perhaps, the costs of visiting relatives. Costs such as this are hard to put a figure on though so it may be easier to just ask for a higher salary rather than the cost of a journey at Christmas that may or may not take place.
Don't ask for too much.