Short answer is some is better than none but if you want to put a bit more thought into it here are a couple of points:
1. Find a course that is geared to the outdoors rather than, say, the 1 day Emergency First Aid at Work course or the 3 Day First Aid at Work courses. Not that they are bad courses but the setting is an urban environment with an ambulance 15 minutes away.
When in the outdoors this isn't an option so an outdoor course looks at the same topics but with the perspective of longer term care of the casualty.
2. Set your budget in terms of time and money. Whilst it would be good to go on a week long expedition course abroad it might not be necessary and we all have to be sensible regarding time and money.
3. I would always recommend a 2 day course for anyone who works or plays in the outdoors. There are lots of providers on the forums so I have to be diplomatic but I know that all of the providers of REC, ITC or ECP awards are all very good and 'singing from the same song sheet' as it were. This is in contrast to the very traditional, urban perspective of Red Cross, St Johns etc. (*no disrespect but I think everyone in the industry recognises that there are different providers a with different remits and capabilities - before I get shot at!*)
A two day course should cover:
- Protecting yourself
- A common Accident procedure - E.g. ABC
- Unconsciousness
- Choking & Breathing problems
- Chest Pain (incl. Heart Attack & Angina)
- CPR
- Serious bleedin
- Shock
- Boney / Joint Injuries
- Specific Injuries: Head, Neck & Chest
- Heat & Cold problems
- Common Medical Conditions e.g. Asthma, Epilepsy, Anaphylaxis & Diabetes
This is a guide. Other providers or awarding bodies may add additional skills. Budget £100-£150 for a 2 day course but make sure it is geared to the outdoors and is full of practical, hands on training and scenarios.
In terms of accidents, bleeding wounds are likely in bushcraft but not as often as you'd thin because we are aware of the danger. Burns are common as are simple ankle sprains. Depending on who you are with; medical problems might be an issue but awarenes can prevent these. On multi day bush trips, poorly tummies and runny botties is a real possible. But again, preventable with education.
Or contact SJA / Red Cross and see what is the shortest course you can get on as quickly as possible. It might also be worth contacting your local authority to see if funding is available (slim chance compared to 4 years ago!) or even asking your employer to put you through an EFAW or FAW courses. This is my area so I am a bit anal about it but I'll be the first to say some training - even a half day basic course - could save a life.
HTH