Thank you, BartoszP! That solved it. I can see everything in the network now.  :D

Here are my updated, unorthodox notes plus printouts. Hopefully they help someone in the future:

Example:
MikroTik LAN IP: 192.168.25.1
LAN DHCP: 192.168.25.100-200

1. IP > Pool > Add New
Name: PPTP-pool
Addresses: 192.168.25.88/29 (192.168.25.88-95)

/ip pool print
# NAME RANGES 
0 default-dhcp 192.168.25.100-192.168.25.200 
1 PPTP-pool 192.168.25.88/29


2. PPP > Profiles > Add New
Name: PPTP-profile
Local Address: 192.168.25.1
Remote Address: PPTP-pool
Use IPv6: No
Use Encryption: Yes
DNS: 8.8.8.8

/ppp profile print detail
1 name="PPTP-profile" local-address=192.168.25.1 remote-address=PPTP-pool 
remote-ipv6-prefix-pool=*0 use-ipv6=no use-mpls=default 
use-compression=default use-vj-compression=default use-encryption=yes 
only-one=default change-tcp-mss=default address-list="" dns-server=8.8.8.8


3. PPP > Secrets > Add New
Name: username
Password: password
Service: pptp
Profile: PPTP-profile

/ppp secret print detail
0 name="username" service=pptp caller-id="" password="password" 
profile=PPTP-profile routes="" limit-bytes-in=0 limit-bytes-out=0


4. PPP > Interface > PPTP Server
Enabled: Yes
Max MTU: 1460
Max MRU: 1460
Default Profile: PPTP-profile
Only check mschap2

/interface pptp-server server print
enabled: yes
max-mtu: 1460
max-mru: 1460
mrru: disabled
authentication: mschap2
keepalive-timeout: 30
default-profile: PPTP-profile


5. Firewall > Filter Rules > Add New
Chain: input
Protocol: 6 (tcp)
Dst. Port: 1723
Comment: PPTP configuration
Drag the new rule to the top of the list (under the Protocol: 1 (icmp) rule)

6. Firewall > Filter Rules > Add New
Chain: input
Protocol: gre
Drag under the Port 1723 rule

/ip firewall filter print detail
0 ;;; default configuration
chain=input action=accept protocol=icmp in-interface=!ether1-gateway
log=no log-prefix=""
1 ;;; PPTP configuration
chain=input action=accept protocol=tcp dst-port=1723 log=no log-prefix=""
2 chain=input action=accept protocol=gre log=no log-prefix=""


7. Set up proxy-arp on the local interface.
Interfaces > ether2
ARP: proxy-arp

/interface ethernet print
# NAME MTU MAC-ADDRESS ARP MASTER-PORT SWITCH
0 R ether1-g... 1500 D4:CA:6D:1C:85:F8 enabled none switch1
1 RS ether2 1500 D4:CA:6D:1C:85:F9 proxy-arp none switch1


8. IP > Firewall > NAT > Add rule
Chain: srcnat
Src. Address: 192.168.25.88/29
Dst. Address: !192.168.25.88/29
Action: masquerade
Comment: PPTP NAT Rule

/ip firewall nat print detail
34 ;;; PPTP NAT Rule
chain=srcnat action=masquerade src-address=192.168.25.88/29 
dst-address=!192.168.25.88/29 log=no log-prefix=""