If you have the chance .. an oil change before "laying up" removes any acids in the oil system and reduces corrosion. As said .. when you run it, it needs to be for a decent length of time to get the WHOLE system, engine, oil, coolant and exhaust up to temperature, otherwise you just cause massive condensation inside all the working bits.
On "nice days" open all the doors and windows to allow the interior to "breathe"
Consider disconnecting the battery, or putting it on charge every couple of weeks, a flat battery left to stand will "die" very quickly
Don't leave lots of petrol in it, petrol slowly "goes off" over time. Its better to put the odd fresh gallon in when you come to run it.
As said .. leave the handbrake off but be aware the "gap" between the disc and pads is very small and corrosion can quickly make it even smaller, leading to the brakes siezing on .. so exercising them on rotating wheels, is pretty important.
When I laid up an MGB for a year did all the above, but also put it on axle stands, was then able to simply spin the wheels by hand once a week, this kept things nice and free. Lowered it and took it around the block (illegaly) every 2 months. Admittedly it was in a garage which made things a tad easier.
Hope things go well for you.. its a lovely motor and I understand why you wish to keep it. Here's hoping things improve and it's soon back where you both belong ... on the road enjoying motoring
