Bad weather outside,do exercise bikes help?
I would just get a good stationary trainer and use your existing bike. I have an old Blackburn, but alas it is unuable with 9-speed hubs. OK though ... lucky to be in CA where we can ride almost all year round.
Spanish Elite cyclist
If you want to keep in shape during bad days I strongly recommend you to buy a stationary trainer. It could be boring, but even with less than hour you can achieve great improvements.
Trainers have the disadvantage of being limited in terms of time spended training(as i said before,it could be boring), therefore you can't stand much more than an hour. You will have to leave your long mileage trainings for good days.
I am Elite cyclists, here in Spain, and i use trainers very often.Until the end of december, I usually ride them two times a week for an hour each time(75-80%MHR), and sundays I get the road to do a three hour ride.
Trainers also gave you a extraordinary point if you want to do a quality workout in the peak of your season. In fact, trainer let you focus in your target without distractions such as cars, traffic lights, etc. That is the reason why I find it so useful in spring to perform absolutely exact my intervals. You will can reduce the total amount of time spended in your training,compared with the one you spend in the road, as you won't have done any "rubbish" miles.
And finally, commentig that i have an Elite Travel Fluid, which works with oil, and i find it interesting in order to search the best price-quality one.
My best wishes for your incoming season;
It's better than nothing.