@TimParris
My desktop is old. It is Dual Quad Core from March 2010. I have babied it along by significantly increasing RAM to 24 GB and my hard drives are Western Digital Black Drives in RAID 1 Mirrored with SCSI with a second set of RAID 1 mirrored internal drives with data only. As well I have two sets of Western Digital MyBook Drives with data only. For a low cost I can have tons of redundancy and plug and play access to my data for a relatively low cost.
Western Digital has replaced the Black Drives with Gold Drives.
Beware that some drives are not RAID compatible.
I have a backup computer to which I attach my portable external MyBook Drives with the data backed up. I use this computer when I take my PC in for physical upgrades.
I replace the power supply every three to four years. I have dual everything - DVD drives, graphics cards, network ports, tons of USB ports.
This really helps with migration.
I am ex-IBM and supported accounting systems migrations for 22 years in high production environments for banking, investment, insurance, government and other raised floor environments. Since moving to tax accounting and bookkeeping it has been a bit of steep learning curve to keep up with changes in technology without my tech team or my former tech buddies in Toronto.
I use Geeks on the Way for remote monitoring and support on a very affordable monthly service plan. This fixed cost price works much better than the vagaries of hourly billing with one person on site tech support. They support North America and have physical support personnel in many major cities. When I need onsite support I pay the very reasonable hourly rate to get a fantastic tech.
http://www.geeksontheway.com/
If and when I physical upgrades in Calgary, I use Memory Express with their bench rates. I need to allow one to two weeks for some service procedures. Usually it takes three to five days since I have a hardware RAID configuration with SCSI connections which not all techs can support. I also need to allow time for special orders to come in. I take the hour year warranty so minimal costs. The bench rates are $50/hr with a fixed time component so a total new install is $150 for a job which may take 4 to 6 hours to complete.
While my Memory Express guys love NAS drives they use it mostly for home entertainment.
My Geeks on the Way (owned by the TURSA Group) guys warn against using NAS as your only backup since you can not access the data directly from your Windows PC OS as you can with a RAID configured Western Digital Drive.
You can set-up a small network using a high speed cable modem and a passive Router to share external drives as attachments between two PC’s. I have been using my 12 port D-Link router since 2008. I have two PC’s and can move my external drives between my two PC’s. I just need to change the file path. I don’t have DoxCycle linked.
If you do go ahead with the NAS drive, then I would use an external set of drives without an OS so that I could easily migrate between systems while you get your apps configured and your files set-up. It can take a while to work out the kinks.
Personally I hate doing this in Jan to May. If at all possible I like to do this in June to August. That said I had to switch systems in February or March three times during the past 21 years. That’s why I have so much redundancy. In an ideal world you would have three systems - Production, Hot Backup (mirrored system), and test. In my mainframe and server days we had two more sets - development and test. But then budgets were very big.
I know that several offices are using MS 365 with MS OneNote to SharePoint pass through. I have no experience with this but have thought that this may be a good alternative for anywhere, anytime, from any device data access. However, I would not be testing this except during off season.
My suggestion would be to add external backup drives for added options for data access while you noodle through your configurations and installations.
Good luck with your migration.