You have to configure one SSTP server in your cloud CHR (or you can buy one routerboard and configure it to your home as SSTP server) with static ip address or ddns service,
then you can simply create on each mikrotik site one sstp client pointing to your sstp server and boom! just configure static router or OSPF and you are ready ! Just connect with your smartphone via vpn!
Network & Security Engineer
Network Solutions Ltd.