Thinking about this, the cheapest solution I can think of is a router with the HDD attached.
This would give you the ability to access them easily where ever you are and on almost all devices. Here is s snippet of info i snagged from the web on the router I use.
( Click to show/hide )Got game? Well, this is the router for you! Built with gaming, streaming and mobile devices in mind, this next generation gigabit WiFi router has a 1GHz dual core processor and delivers extreme speed so you enjoy less lag and less buffering. With Beamforming+ and built in high powered amplifiers and external antennas, get ready for the extreme! Nighthawk also has you covered even when you're away from home. Features such as NETGEAR genieŽ remote access, ReadyCLOUDŽ, OpenVPN, and Kwilt app support help you manage your network, have access to a secure personal cloud, access home network remotely, and share photos stored on the storage from anywhere. Using Amazon Alexa™, control your home network with voice commands.
Obviously this is the bare bones but at least a temp solution until you want to set up the NAS.