If Ratcliffe gets the nod, which I don't believe he will, he can implement changes to the training facilities and Old Trafford gradually. There's no need to immediately rebuild both.
The Glazers have themselves invested (the club's money, of course) into improving both on this basis.
Work to be done absolutely, but it isn't the most immediate concern.
Sir Jim will inherit some of the same challenges that the Glazers have created.
1. He will need to pay dividends to keep the Class A group happy, if that is really possible, if they miss out on what you would think was their dream scenario, doubling their share value, they will need convincing.
2. Because of the Class A group Sir Jim is unlikely to just hand over money, this would mean he loses 33% to the class A shareholders in addition to any remnant Glazers.
3. The main way he would be able to add investment, to the club, would be to give soft loans to the company, repayable if he sells etc. Someone with experience of such finance may be able to clarify. So this may be the Old Trafford/training ground stuff.
On the other hand he can write off his share of losses/soft loans against his Ineos profits but it all appears very complicated.